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Friday, July 15, 2022

The Constitution of Medical Knowledge

Patients are often confused by seemingly conflicting findings of studies, or equally good doctors recommending different treatment plans. How are we to decide? Medical science is a process created by a “reality-based community” to help decide such questions. Science isn’t just hypothesis-testing with empirical observation, although that is a big part of it. It is also the consensus of a community of experts. In 1660, scientists led by Isaac Newton formed The Royal Society as the first institution designed to collect, encourage, and evaluate scientific knowledge. They published the first scientific journal in 1665 (which is still in publication). Were they ever wrong? Often! For example, for 250 years everyone wrongly believed Newton’s theory that gravity was a fundamental force of nature. And that is the point – knowledge is fallible and not subject to the personal authority of any one person. But over time, the arc of the universe of scientific knowledge bends towards truth.

There have been many improvements to the system of medical science since the Scientific Revolution. The first peer-reviewed journal was published in 1731. But peer-review as we now know it didn’t begin until the 1970s. The first randomized clinical trial occurred in 1747 (citrus for scurvy), but the rules for running double-blinded randomized clinical trials, and progressive Phase 1-3 trials weren’t systematized until Austin Bradford Hill and Harry Gold in the post-WWII era. Statistics entered medicine in the 1970s. Systematic reviews began in the late 1970s. Evidence-based medicine, as we know it today, was taught in medical schools since the 1980s.

Jonathan Rauch in “The Constitution of Knowledge: A Defense of Truth” describes knowledge as a funnel. At the top are all the guesses, the hypotheses, that drive scientific investigation. This would include (in order of increasing reliability):

5. Much of what is posted on any patient health forum every day: anecdotal “evidence” from patients; YouTube videos posted by Snuffy Myers, Mark Scholz, etc.; lab studies (mouse or test-tube); 

4. observational/epidemiological studies of patients; 

3. retrospective case-controlled studies, and systematic reviews/meta-analyses of them; 

2. cohort studies (people followed from before disease occurrence; e.g., Health Professionals Follow-Up Study, Mendelian Randomization Study). 

All of them are just hypothesis-generating. Most hypotheses are, and should be, wrong. Science depends on evaluating lots of hypotheses. There is no shame in guessing wrong; the only problems are when guessing stops and when one confuses a guess for a fact.

1. Large, well-done, and confirmed randomized clinical trials are at the bottom of the funnel; they are not just hypothesis-generating, they constitute truth in medical science. These categories were universally agreed upon after looking at which kinds of studies are likely to have conflicting results, and which almost never have conflicting results. All scientists believe in these categories; “pseudoscience” occurs when people claim to be doing science but ignore these categories. 

Here’s a fuller description:


Some institutions regularly GRADE prostate cancer research (NCCN, AUA, ASTRO, ASCO, SUO, EAU, CUA, PCF, and others). The institutional opinions (and not anyone’s personal opinion) are the standard-of-care. Until disproved, they constitute current medical truth. While even the best research doesn’t predict for the individual, one is foolish to ignore our best estimate.

There is no science without consensus by experts - science is a social construct. One can argue that there are and always have been objective truths, but we can only know what is in some way perceivable by humans. Did the Earth always revolve around the sun? Of course. But it did not enter the realm of science until Copernicus hypothesized it (1543), and Galileo (1609), Tycho Brahe (1573), Johannes Kepler (1609), and Isaac Newton (1687) proved it and showed how. That’s when astronomy became a science. There is no science without hypothesis-testing and empirical observers. 

 Loss of Respect for Expertise 

How do we know what is true? None of us has the time or the inclination to test everything for ourselves. We rely on trusted experts to tell us. Few doubt that the heart pumps blood to our lungs and other tissues, although few have seen our hearts do that. We know that William Harvey discovered that fact in 1628, and it is now universally accepted as true and foundational to all cardiology. Even fewer know how the cardiac tissues cause the heart to beat, how arrhythmias are diagnosed, or how plaques can cause heart attacks. We rely on cardiologists to know all that, and within cardiology are sub-specialties (e.g., heart transplant specialists, sports cardiology, electrophysiology, etc.). There are dozens of medical specialties, each with several sub-specialties. There are even specialists in cutting across categories, and assuring that the latest innovations become available to patients; this is called “translational medicine.” In this era of specialization, few know much outside of their specialty, and as patients, we must, at some point, rely on the experts for our knowledge about disease, diagnosis, and treatment. 

Medical science became probabilistic in the 20th Century. All medical institutions agreed that statistics are the only way to reject hypotheses, judge superiority or inferiority, infer causality, and to analyze and reduce errors. Statistics are difficult to understand and are non-intuitive, even for many doctors. As sophisticated statistical techniques were adopted by the medical institutions and their publications, lay people, who did not have their arcane knowledge, were increasingly left out of the truth community. 

The Dunning-Kruger Effect is a cognitive bias on the part of incompetent people overestimating how much they know. In medicine, a little knowledge is a dangerous thing. When I started writing my novel, Thaw’s Hammer, about a killer virus, I thought I knew enough about the subject to write a credible novel. Four years later, I knew how much I didn’t know. I grew to admire the experts who had to understand the biochemistry of the replicative apparatus, the interactions with host cells, and the immune system. Viruses are the most numerous and diverse forms of life on Earth. Anyone who thinks they fully understand them is wrong. The experts differ from lay people in knowing they don’t completely understand them. Still, an expert understands a lot more than any lay person who thinks he knows more. I know enough to reject any advice from a Jenny McCarthy or a Joe Rogan in favor of advice from the CDC. 

Overconfidence in subjective assessments, when contrary to scientific consensus, is also influenced by alignment with political and religious social groups. The Dunning-Kruger Effect is particularly strong on the issues of vaccination (particularly Covid-19 vaccination), genetically modified foods, and homeopathic medicines (see this link).

Fundamentalism in Medicine

Knowledge is progressive and cumulative. Newton said, “If I have seen farther, it is because I have stood on the shoulders of giants.” Opposing this kind of humility, are people who think, based on a few facts or “alternate facts,” that they have arrived at the truth hidden from the rest of us. What they are really doing is inhabiting what Rauch calls an “epistemic (knowledge) bubble.” They are only allowing into their knowledge bubble those data, and persons, that confirm their biases. They take studies out of context and fail to rigorously analyze studies they agree with while finding reasons to disqualify studies that don’t agree with their preconceived notions. They reject the methods of analysis developed by the institutions they reject. They are usually smart and think that they are fully capable of judging the data for themselves. This takes a certain kind of narcissism – as if the whole world is full of “sheeple” and only they know the real truth. They are also lazy – it would be too much work to learn and evaluate the whole body of knowledge. 

Fundamentalism has been around in religion at least since the Protestant Reformation. But it emerges in all other areas of human knowledge – politics (as populism), law (as originalism/ anti-stare decisis), and folk/Internet medicine. It is usually short-lived: the fundamentalists of one generation eventually give way to the acceptance of an orthodoxy and hermeneutics for interpretation of texts. Fundamentalism substitutes personal authority for institutional authority. Personal knowledge is acquired rapidly and doesn’t require input from others. Because personal ego is at stake, it excludes all information that doesn’t confirm. Institutional knowledge, on the other hand, builds on a foundation of knowledge of the “truth community,” and includes conflicting data. The conflicting data create new hypotheses and the opportunity for knowledge to expand. If enough conflicting data accumulate, they may cause what Thomas Kuhn called a “paradigm shift.” 

Google is a wonderful thing. Knowledge is potentially at our fingertips, but information out of context can mislead. Instead of knowledge, we can be left with information that only confirms what we think we know. Social media ideally expose us to all sides of any issue. But if we are not open to all sides, social media can only reinforce the knowledge bubble we have built around our pre-determined beliefs. Without challenges to what we think we know, there is no progress. 

Distrust of Institutions 

There has been growing distrust of institutions among lay people, sometimes with good reasons. There were abuses like “p-hacking” that fostered distrust. Until recently, publications did not require authors to be transparent about potential conflicts of interest. Often, negative findings were not published (the US government now requires all registered clinical trials to publish their findings). Budget cutbacks at the NIH decreased funding for medicines and technologies that did not have profit potential. Mistakes and abuses were publicized in the media and over the Internet. Institutions are valuable not because they don’t make mistakes, but because they correct mistakes and abuses. Retractions and corrections are published. Researchers who lie are found out and excluded from future publication. 

The other threat to truth came from an unlikely source – conspiracy theorists. Before the Internet, they were just isolated “nut jobs.” But social media provided the means for them to find others with enough common beliefs to form a “non-truth” community. On the patient forum, HealthUnlocked, I’ve seen several who point to a supposed Big Pharma/FDA conspiracy. Although they are still a minority, they can have outsize influence by dominating conversations, mixing truth and lies, purveying lies so outrageous that some believe there must be some truth to them, and by blinding the conversation with so much bullshit that reasonable people despair of ever discerning the truth. On Facebook, Twitter and YouTube, bad actors can stage a concerted campaign to “like” and “share” content they want to use as propaganda. They can “troll” serious posts to render the conversation harder to follow. 

Because institutional knowledge was not readily comprehensible to laymen, and because distrust mounted as abuses were well-publicized, the Internet (Dr. Google) became a substitute for expertise. Laymen believed they understood the subjects as well as experts and their institutions, and they were able to find others on social media willing to tell them so. When biases are confirmed by media personalities they become particularly pernicious. We always believe relatable people we know and like (from TV, videos, and podcasts) versus strangers who author incomprehensible studies full of numbers and jargon we don’t understand. This cognitive error is called “the availability heuristic” – it’s why you may believe the claims of someone you know on an Internet forum over high-level statistical evidence. The danger of substituting personal knowledge for institutional knowledge in medicine became apparent with the anti-vaxxer movement. It had always been a fringe group, but in the US, a third of the population did not get vaccinated against Covid-19.

What can be done?

What can be done to restore faith in institutional truth? Rauch sees hope in the measures Facebook took after it came to light that bad actors from Russia manipulated Facebook’s algorithms to change what was seen by Facebook members. Facebook changed its algorithms and created software to eliminate bots. They also labeled and demoted content of dubious veracity. They established an independent oversight board with transparent rules. It reports to and is financed by independent trustees, who can remove its members if they act in bad faith. The board’s decisions are binding on Facebook and anyone who uses Facebook. Its decisions are published. It acts much like an independent court. The problem for a patient health forum like HealthUnlocked is that unless the oversight body is a panel of doctors, they cannot privilege the content of one post over another without risking lawsuits.

The most any patient forum can do is establish rules for civil discourse. I would suggest the following rules and guidelines for anyone posting in a patient forum:

(1) No ad hominem remarks. Ad hominems are remarks that insult the person. “You’re wrong about that and here’s why…” is entirely appropriate. “Jane, you ignorant slut!” is entirely inappropriate. Responses must speak to content, not the supposed intentions of the poster. If you don’t have anything good to say about a person, say nothing. This should eliminate trolling. Trolls thrive on attention and virtue-signaling, so don’t feed the trolls by responding in kind. Alert a moderator immediately. If you feel you have to make personal remarks, do it in private mail.

(2) Members cannot post dangerous or illegal content (e.g., a recipe for a known toxic substance or instructions on how to obtain it). They may post unproven or experimental therapies, and especially their own experience with them. Members are encouraged to identify experimental therapies as experimental. Hypotheses are entirely appropriate and encouraged.

(3) Avoid strawman arguments. Strawman arguments are ones that replace what the poster is actually saying with a false one which is then refuted. If you are starting a reply with the words “"So what you're saying is ... ?" or “Then you must also believe that…” you are probably setting up a strawman. The opposite is a steelman argument, where you restate what the poster said in the strongest form. It shows you are listening and want to resolve the issue.

(4) Avoid sarcasm. Sarcasm doesn’t work on the Internet. It usually only works if one can see your facial expressions and hear it in your voice. There are no sarcasm emojis, and the original poster will probably believe you meant it seriously. Making fun of a person is just a form of ad hominem. Humor is fine, but not as a rhetorical technique.

(5) Be aware that consensus is rare. Patients may get a lot of conflicting advice or anecdotes, and that’s okay. Discuss with a doctor you trust.

(6) Don’t take it personally if someone disagrees with you. Consider the issue as dispassionately as you can. It’s not necessary to reach agreement, just to flesh out the issue from all sides.

(7) Caveat emptor! No one on a patient forum is a doctor, and no one’s advice or personal experience should be taken as definitive. Anecdotes are not evidence. Check everything with your doctor. It is entirely appropriate to ask for source material for advice that goes beyond the standard-of-care, and to discuss those sources with your doctor. But remember that doctors may have little patience for sources that do not come from peer-reviewed journals or are low-level or low-quality evidence (see above).


Thursday, April 28, 2022

The importance of radiotherapy dose escalation and long-term ADT for success

 Localized prostate cancer (PCa) is highly curable. We usually divide localized PCa into 3 risk categories: low-risk, intermediate-risk, and high-risk of recurrence after treatment. Even high-risk PCa is highly curable - 80+% of patients are cured in clinical trials of various radiation therapy regimes (see this link, for example). With new PET scans recently approved for high-risk patients, patients who truly have localized PCa have every hope of achieving even better cure rates.

This begs the question: what do we mean by "cured." What most patients mean is that no recurrence will ever be detected. The first sign of recurrence is a rising PSA more than 2.0 ng/ml over the lowest PSA achieved (nadir). This is called a "biochemical recurrence" (BCR). Other deleterious events may happen. An undetected ("occult") metastasis may grow. The patient may die due to some other cause. If the former never happens, it is called "metastasis-free survival (MFS)." It is highly dependent on the technology used to detect occult metastases. If the latter never happens within the time patients are tracked after treatment, it is called "overall survival (OS)." It is highly dependent upon other diseases ("comorbidities"), treatments given, and the length of follow-up. Often, there are undetermined variables (called "confounders") that tilt OS in one direction or another. Only BCR is relevant for the patient making a therapy choice for his localized prostate cancer.

As we saw previously (at this link), the MARCAP consortium has found that the duration of androgen deprivation therapy (ADT) given along with ("adjuvant to") radiation therapy depends on how the radiation is delivered to high-risk patients - either 12 months for brachy boost therapy or 26 months for external beam radiation therapy. Kishan et al. has analyzed a large number of clinical trials to answer the following questions:

  1. What is the role of radiation dose escalation in minimizing BCR?
  2. What is the role of long-term vs short-term ADT in minimizing BCR?

  • They defined "high dose" radiation as any dose equivalent to greater than or equal to 74 Gy (or its equivalent)
  • They defined "long-term" (LTADT) as any duration longer than 18 months, while "short-term" (STADT) was defined as 3-6 months.

For high-risk patients, compared to treating them with low-dose RT without ADT:

  • Adding high dose RT (without ADT) reduced BCR by 26%
  • Adding short-term ADT reduced BCR by 36%
  • Adding high dose RT and STADT reduced BCR by 55%
  • Adding low dose RT and LTADT reduced BCR by 61%
  • Adding high dose RT and LTADT reduced BCR by 69%

Intermediate risk patients were treated before NCCN distinguished "favorable" intermediate-risk from "unfavorable" intermediate-risk (see this link). For intermediate-risk patients, taken as a whole, compared to treating them with low-dose RT without ADT:

  • Adding high dose RT (without ADT) reduced BCR by 21%
  • Adding short-term ADT reduced BCR by 32%
  • Adding high dose RT and STADT reduced BCR by 46%
  • Adding low dose RT and LTADT reduced BCR by 55%
  • Adding high dose RT and LTADT reduced BCR by 74%
In both risk groups, long-term ADT provided greater benefit than high dose RT, but combining LTADT with high dose RT provided the best cure rates. 

There are some seeming contradictions between this meta-analysis and the DART 01/05 randomized clinical trial. The purpose was to see if there was a difference in biochemical disease-free survival (bDFS) among intermediate and high-risk patients treated with high-dose radiation and either 28 months or 4 months of ADT. At 5 years of follow-up (see this link), the LTADT group had a significantly higher bDFS than the STADT group. The difference was particularly noticed among the high-risk subgroup. However, with 10 years of follow-up, the difference was no longer significant. 
  • For the total, the bDFS was 70% for LTADT vs 62% for STADT (not statistically significant)
  • For the high-risk subgroup, the bDFS was 67% for LTADT vs 54% for STADT (not statistically significant)
At least for the high-risk subgroup, the difference was large but not statistically significant. What happened?

What happened was a quarter of the men in the study died in the interim (median age was 72 at the start). Only 3% died of prostate cancer. Many of the men who would have shown no biochemical progression had they lived were eliminated from the trial because they died of other causes. This is called "survivorship bias." The high dropout rate due to death from other causes tells us that follow-up of such trials beyond 5 years will introduce bias into our most important endpoint. It is also another reason that "overall survival" is not a useful endpoint when patients are older. Men with less than 10 years of expected survival due to age or comorbidities should consider watchful waiting rather than any kind of radical treatment. Patients can determine their actuarial expected survival with this calculator: (scroll down to "Male Life Expectancy").






Saturday, January 22, 2022

Optimal duration of adjuvant ADT depends on the type of radiation used for high-risk patients

No one wants to have androgen deprivation therapy (ADT), even if it is for a limited time. It has been known for a long time that it improves oncological outcomes when given with ("adjuvant to") radiation therapy in patients with high-risk prostate cancer. Several randomized clinical trials (RCTs) have tried to find the best duration to use it, but it is difficult to arrive at reliable optimization points- it would involve varying the duration for a large number of high risk patients. Kishan et al. have taken an innovative approach to solving this problem by combining several RCTs and a multi-institutional observational study. Unlike typical "meta-analyses," they compared similar patients across three studies.

The three studies they used in their analysis were:

  1. The high-risk patients in the DART 01.05 GICOR RCT (see this link), which randomized patients to 28 months or 4 months of adjuvant ADT in patients getting high dose external beam radiation (EBRT-only). They found that 28 months is better than 4 months, but is there a duration that is less than 28 months for EBRT-only?
  2. The patients in the TROG 03.04 RADAR RCT (see this link), which randomized patients to 18 months or 6 months of adjuvant ADT in patients getting varying doses of EBRT or high dose rate brachy boost therapy (BBT). They found that 18 months is better than 6 months for BBT, but is there a duration that is less than 18 months for BBT?
  3. The patients in a multi-institutional (retrospective, non-randomized) study who received varying durations of adjuvant ADT and EBRT-only or brachy boost therapy for their high risk PCa (see this link).

They used distant metastasis-free survival (DMFS) as the endpoint of interest because it has been found to correlate well with eventual overall survival. They went back to the original patient-level data to extract comparable patients when comparing them across studies. This retained many of the advantages of each of the three studies. While this innovative approach does not constitute the highest level of evidence (Level 1), it offers a degree of reliability that goes beyond simple observational studies.

They used two statistical methods to look at the data. In one analysis, they divided the durations into three parts: 

  • ≤6mo.
  • >6 - 18 mos
  • >18 mos

In another analysis (called "cubic splines") they found the best fit for the continuous data. Both analyses led to similar conclusions.

The best estimates for the best minimum adjuvant ADT duration are:

  • at least 26.3 months for EBRT-only
  • at least 12 months for BBT

But, one might object, didn't Nabid's PCS IV trial show that 18 months is as good as 36 months (see this link)? Kishan points out that only about half of the cohort in that trial who were supposed to get 36 months of ADT actually got that much. And nearly a quarter of the 36-month cohort actually received less than 21 months. The only data we've seen so far has been analyzed by the dose they were intended to get, not by what they actually got. Also, why were the drop-out rates so high? The DART RCT had 95% compliance with the full 28 months, even though the radiation doses given were much higher.

There is a trade-off: BBT can come with severe late-term urinary side effects (among 19% in the ASCENDE-RT RCT), while the late-term urinary side effects are milder for EBRT-only (only 2.5% in DART). Only the patient can decide if he is willing to take on 12 months of ADT with BBT vs over twice as long for EBRT-only, given the higher expected radiation toxicity with BBT.

Which is better: EBRT+2 years of ADT or BBT+1 year of ADT?

Patel et al. looked at the use of the two therapies at many of the top cancer centers. They found there was no significant difference in the occurrence of distant metastases or in prostate cancer-specific survival.

There are several unanswered questions:

  • As we have seen (see this link), brief intense use of abiraterone or other advanced hormone therapy may obviate the need for longer ADT.
  • Decipher genomic analysis may indicate which patients may be able to get away with less hormone therapy, and which need more. The PREDICT-RT RCT will eventually answer this question.
  • Does SBRT monotherapy or HDR brachy monotherapy still require adjuvant ADT? Those therapies can have almost as high a biologically effective dose as BBT but with fewer side effects. This study suggests that 12 months of ADT is beneficial with even the highest dose radiation, but future clinical trials will give a more reliable answer.
  • Standard-of-care dictates 2-3 years of adjuvant ADT when enlarged pelvic lymph nodes are found by CT or MRI. What is the optimum duration when cancerous pelvic lymph nodes are only detected with a PSMA PET scan and not by CT? What about when they are too small to be detected by any kind of imaging, and their presence is only suggested by risk characteristics?
  • What duration of adjuvant ADT minimizes biochemical recurrence-free survival and the need for any salvage treatment?
  • Will these estimates hold up if tested in an RCT?

Sunday, December 12, 2021

Gay men should never* have a prostatectomy

After over 10 years with gay prostate cancer support groups, I have come to believe that radical prostatectomies (RP) cause special and needless suffering in gay men and should never be used in them. Two great resources for gay men faced with this decision are these:

The Effects of Radical Prostatectomy on Gay and Bisexual Men's Mental Health, Sexual Identity and Relationships: Qualitative Results from the Restore Study

Threat of Sexual Disqualification: The Consequences of Erectile Dysfunction and Other Sexual Changes for Gay and Bisexual Men With Prostate Cancer

Gay men suffer more from prostate cancer

The distress caused by a prostate cancer treatment is worse for gay men than for straight men (HartUssherRosser). The excess distress among the "boomer" cohort may be rooted in a lower perception of societal status to begin with (discussed in The Velvet Rage), and the adoption of dominant culture point-of-view of gay men as hypermasculine or effeminate, and hypersexualized. The greatest threat to the identity of gay men with prostate cancer is the loss of erectile function.

"Just cut it out"

"Cancer panic" is a type of anxiety familiar to everyone who has had a cancer diagnosis. It is often followed by generalized depression and grieving over one's mortality. Anxiety and depression are the enemies of understanding. There is very little input that can occur. From the doctor's point of view, a great deal of information is imparted. But from the patient's point of view, all he may hear is "cancer blah blah blah."

For most of us, cancer seems to be an unvaryingly lethal disease. We all have loved ones who have died, sometimes painfully, from various types of cancer. The fact that prostate cancer is uniquely slow growing and we have biomarkers and diagnostic tests that often allow it to be cured is lost on many of us, if not intellectually, at least emotionally.

"Just cut it out" is a very natural first reaction. Often, well-meaning family and friends reinforce that initial reaction.

Results the same or better with radiation or active surveillance

The ProtecT clinical trial randomized men with localized prostate cancer to either active monitoring, radical prostatectomy (RP), or external beam radiation (EBRT). After 10 years there was no difference in oncological outcomes. While ProtecT didn't break down results by risk level (almost everyone was favorable risk), we now know that 55% of low-risk men are able to go without treatment for 20 years so far without grade progression (Klotz). Favorable intermediate-risk men have similar 10-year results with RP or SBRT. Unfavorable intermediate-risk men seem to have superior results with radiation (see this link), and high-risk men have much better results with brachy boost therapy than surgery (Kishan et al. 2018).

There were marked differences, however, in quality-of-life in ProtecT. There was higher risk of lasting incontinence and erectile dysfunction after prostatectomy.

Among men who were previously potent, only 35% maintained potency 2 years after nerve-sparing prostatectomy (Sanda et al, 2008). It was similar to EBRT in men who were 10 years older. Using better radiation techniques (like SBRT) has resulted in 2-year potency preservation of 79% (Chen et al.). Of course, active surveillance results in no incremental potency loss.

Age

Younger men do better with any therapy - RP or RT. When we are younger, our tissues are more resilient. Some have used that as an excuse for younger men to avoid active surveillance. In fact, there is no age at which active surveillance is not preferable in terms of long-term side effects (see this link and Lee et al.).

It has been argued that the risk of a second primary malignancy due to radiation is a major risk factor in younger patients. This recent study found that the "Probability of Second Malignancy was similar between SBRT and radical prostatectomy." It is tremendously difficult to attribute second malignancies to radiation. Hensley et al. has shown that men who have had bladder cancer (removed by cystectomy) are more prone to prostate cancer. The best estimates of risk are less than 1% (see this link and this one). Arguably, younger men have more intact DNA repair mechanisms.

Young, unpartnered and gay men are particularly impacted by "marginalisation, isolation and stigma—relating to men's sense of being “out of sync”; the burden of emotional and embodied vulnerabilities and the assault on identity." (Matheson et al.) A recent Pew study reported that gays are much more likely to be single than straights, especially gays over 45 (AARP). Gay men of all ages do not have the social support system of their straight counterparts.

Aging without expected erectile function is especially a problem for gay men (Ussher et al.)

Erectile Dysfunction

Even among men who are able to regain erections sufficient for vaginal penetration, they are seldom able to regain erections sufficient for anal penetration. At Memorial Sloan Kettering, arguably one of the best institutions at providing quality RP, "only 4% of men who were ≥ 60 years old with functional erections pre-surgery achieved back-to-baseline erectile function." (Nelson et al.) I would guess that drops to near zero for anal penetration.

As mentioned, erectile dysfunction is the single largest emotional and social problem for gay men, who are mostly single at the age when they are treated for prostate cancer. Gay men more than straight men face an identity crisis because their identities have been sexualized. With only 35% maintaining potency after RP, and even fewer left with erections sufficient for anal intercourse, they are effectively excluded from the dating market and face a lifetime of social isolation. Ussher et al. (2017) calls it "sexual disqualification"- exclusion from gay life.

The sudden loss of potency destroys many pre-existing relationships. Partners look for sexual satisfaction elsewhere, and often leave relationships as a result. Depression is a common result. There have been no studies of suicide following RP among gay men, an unmet need.

While orgasm is still achievable without an erection, many men do not find it worth the bother.

Loss of Ejaculate

While women can fake orgasms, men can't. We either ejaculate at orgasm, or we don't have an orgasm. Ejaculation is how men communicate that "it was good for me." Men are disappointed when their partners do not "cum." RP removes all ejaculate except for Cowper's gland secretions. RT reduces ejaculation, but in a recent trial of SBRT patients at Georgetown, only 15% were without ejaculate after 2 years. Anejaculation excludes men from relationships with other gay men. It is more bothersome to gay men (Wassersug et al.)

Ejaculation is how we've signaled orgasm to ourselves since puberty. Getting used to orgasms without ejaculation takes some psychological readjustment, whether gay or straight.

Perceived size loss

Another rarely discussed adverse effect of RP is size loss. Men are very conscious of size and compare themselves to others. Size is seen as a surrogate for masculinity, and many think that sufficient size is necessary for mutual pleasure. Size loss is difficult to measure objectively, but the perception of size loss can be patient-reported (but usually isn't). In a patient-reported study of 1411 men, 55% of men report size loss after RP (Carlsson et al.)That loss had a negative effect on their quality of life. Some patients complain that even sitting down to pee they are unable to point their micropenis into the toilet. Gay men with such size loss universally do not undress in front of others.

Climacturia

Shooting urine at orgasm (climacturia) is another non-regularly reported side effect of RP. Incidence was as high as 44% at 3 months post RP and 36% at 24 months post RP (Mitchell et al.). For many men, gay or straight, it is embarrassing and bothersome. Many give up sex because of it.

Penile sensitivity/dysorgasmia

Because of damage to the pudendal nerve during RP, some men report penile pain (usually temporary) or loss of sensitivity (maybe permanent). Perhaps related is reported pain during orgasm(this seldom occurs). This is often not reported.

Anal Pleasure

I've heard mixed reports about whether receptive anal sex (bottoming) is as pleasurable post-prostatectomy. Some feel that pushing against the prostate and pushing out cum is an important source of pleasure. Others feel that filling the rectum is all that's necessary. Ussher reports that many men who are in relationships who previously enjoyed "topping" switched to bottoming when they could no longer perform. Many were unhappy about switching roles. This has only been qualitatively researched.

Myths

There are two myths that are prevalent about radiation, and they affect decision-making among gays and straights equally. The first myth is that salvage after radiation is nearly impossible. While it is true that surgery after radiation is fraught with peril and should never be done, it is untrue that no salvage is possible. In fact, salvage after RT often has better results both oncologically and in terms of side effects compared to salvage RT after surgery (see this link). More to the point, with 10-year biochemical recurrence-free survival after RT over 95% for favorable risk, and over 80% for the highest risk patients, and with better PSMA PET patient selection, salvage should not be an overriding concern. It is a mistake to think that one can always have salvage. Side effects are always worse than if RT had been given originally.

The other myth is that with radiation, side effects crop up with time. One need only look at the patient-reported outcomes in the 6 years of the ProtecT trial to see it isn't true (see this link). With radiation, acute side effects are highest in the first 6 months and decrease afterward. That is not to say there are no late-term effects, but it is extremely rare for an entirely new side effect to occur later that has never occurred before. Erectile dysfunction naturally increases over time as men age. In a very elegant study, Keyes et al. showed that half of the long-term decline in erectile function among men getting brachytherapy was due to normal aging. ED does occur with radiation, but there is significantly less.

ADT

It is worth mentioning that those with advanced prostate cancer who must use ADT, often complain of their loss of masculinity. When RT is used for high-risk localized prostate cancer, adjuvant ADT is temporary. However, if proper preventive measures aren't taken (e.g., penis pump), there could be permanent size loss.

Lack of Research

The major instruments/questionnaires for evaluating quality-of-life after treatment, EPIC and SHIM, do not ask about most of the above adverse effects of treatments. Indeed, they do not ask men if they have sex with other men. What does not get measured, does not get acted upon. If there are any solutions to the above adverse effects of RP, they are not being studied intensively, if at all.

Most urologists have no idea if their patients are gay or straight. Sometimes they bring their male partner if they have one. But most often they are not out to their doctor because they are fearful that their doctor may have anti-gay attitudes and will somehow provide lesser treatment.

Advice

Slow it down!: For men diagnosed with localized prostate cancer, there is ample time to make a decision. Treatment delays have been studied (see this link), and treatment delays of 3 months, even in high-risk men, do not make a difference in outcomes. Your initial cancer panic will subside with time, and you will be able to make a more reasonable decision. Doctors should never accept a treatment decision within one month of diagnosis, and probably not even within 3 months, especially with the approval of PSMA PET scans for unfavorable risk patients. If your diagnosis is low-risk, join an active surveillance program. Even some favorable intermediate-risk men with small amounts of pattern 4 can buy time on active surveillance.

Tell your doctor that you're gay. Very few are bigots in major cities. If you live in Buttfuck, KY you should not have a prostatectomy there anyway. Remember that your doctor is of limited use in helping you grapple with the emotions necessary or even provide much of the information necessary to make this decision, and won't be there to pick up the pieces afterwards. A recent NY Times article described a novel program at Nothwestern University in Chicago to help gay men after prostate cancer treatment.

Join a support group. One can read all about this stuff, but things like loss of ejaculate and size loss won't be real to you unless you experience them. The next best thing is talking to a live person who has experienced them. (This is called the "availability heuristic," by the way.) It is one thing to understand intellectually, but quite another to feel it. Seeing a grown man cry about his micropenis has more impact than reading that penile shortening occurs.

Go into psychotherapy/ learn mindfulness: We all have baggage about cancer. Learn what kind of baggage you are carrying and whether you are hampered by it. If you can, take a class in mindfulness. With practice, it will help you stay in the present moment instead of ruminating endlessly about low probability future outcomes.

Talk to a Radiation Oncologist: We all started with a urologist. Sometimes, he did your biopsy. Many are trained as surgeons. Some surgeons are "hot dogs" who believe they can cure the common cold. They usually recommend surgery, because it's what they do. (If they don't believe in surgery, they wouldn't be a surgeon.) Get out and find a radiation oncologist before you make a treatment decision.

Don't ask the doctor what he would do if you were his father! This is probably the question patients most often ask, but shouldn't. You are asking one specialist to also be a specialist in another therapy. A doctor well-trained in shared decision-making will deflect your question: "what more can I tell you, so that you feel able to make this decision for yourself?" Even if the doctor is gay, he is not you - he has his own set of concerns and biases.

*OK, there are exceptions, but very few.

(1) There are very few men who are super-sensitive to radiation cannot have it. 

(2) Some men have BPH to such a degree that radiation will inflame the prostate and cause the urethra to close up. Most such men can have a TURP procedure before radiation. TURPs usually cause reverse ejaculation (semen goes up into the bladder). But it is also necessary to wait several months before radiation begins; otherwise, there is risk of incontinence. 

(3) Men with a history of intractable relapsing prostatitis. 

Thursday, June 3, 2021

Brief, intense radiation and hormone therapy for very high risk prostate cancer

(updated)

As we've seen, brachy boost therapy seems to have the best oncological results for men with very high-risk prostate cancer. But brachy boost therapy entails 20-25 external beam radiation treatments plus the invasive placement of radioactive seeds or needles plus at least 18 months of testosterone suppression. While the oncological results are excellent, with about 80% cure rates, there is significant risk of serious late-term urinary retention. In some men, testosterone never fully recovers.

McBride et al. reported the early results of the AASUR trial. The goal of the trial was to find a treatment with equivalent oncological outcomes, but one that is easier on the patient, with less risk of long-term toxicity. They recruited 64 patients at 4 top institutions (Memorial Sloan Kettering, Johns Hopkins, University of Michigan, and Thomas Jefferson University). All patients were "very high risk," defined as:

  • any Gleason score (GS) 9 or 10, or
  • 4 or more cores of GS 8, or
  • 2 high-risk features (stage T3/4, GS 8, or PSA>20)
  • No metastases (N0, M0)

Patients were treated with:

  • SBRT (7.5-8.0 Gy x 5 treatments)
  • 6 months of Lupron, Erleada, and Zytiga

After 30 months of follow-up:

  • 90% were free of biochemical failure
  • Median PSA at the last follow-up was 0.1
  • PSA remained undetectable in 40%
  • Testosterone rose to non-castrate levels at a median of 6.5 months after hormone therapy ended, and almost all rose to >150 ng/dl
  • 23% experienced transient serious toxicities, mostly hypertension
  • Quality of life scores at 1 year held for urinary and rectal domains but declined in sexual and hormone domains.

How do these results compare to other trials of radiation+ADT in high-risk patients?

Lin et al. used whole pelvic IMRT with an SBRT boost to the prostate and 2 years of ADT in 41 high- and very high-risk patients. With 4 years of follow-up, they reported 92% biochemical recurrence-free survival (bRFS).

Hoskin et al. used high dose rate brachytherapy as a monotherapy in 86 high-risk patients. Most (80%) had adjuvant ADT for a median of 6.3 months (range 1-40 months). With 4 years of follow-up, they report 87% biochemical recurrence-free survival (bRFS) among high-risk patients.

Zapatero et al. reported the results of the DART 01.03 GICOR trial of escalated dose IMRT with either short-term (4 months) or long-term (28 months) ADT. There were 185 high-risk patients with about half getting each ADT protocol. About a quarter received simultaneous radiation of their pelvic lymph nodes. With 5 years of follow-up, they report 76% bRFS among high-risk patients who got short-term ADT and 88% bRFS among high-risk patients who got long-term ADT.

(Update) Murthy et al. reported results of a trial where 224 men with ≥ 20% risk of pelvic lymph node metastases were screened with PSMA PET scans and were randomized to get whole pelvic radiation with a boost to the prostate or prostate-only radiation. They all received 2 years of adjuvant ADT. With 5 years of follow-up, they reported 95% bRFS. 

This table summarizes these trials:


AASUR

SBRT boost

(Lin)

HDR-BT

(Hoskin)

IMRT

DART 

GICOR

IMRT

DART 

GICOR

IMRT

POP-RT

follow-up

2.5 yrs

4 yrs

4 yrs

5 yrs

5 yrs

5 yrs

Radiation

SBRT

IMRT+

SBRT boost

HDR-BT 

monotherapy

IMRT 

(dose escalated)

IMRT 

(dose escalated)

WP:50Gy/25fx

boost:18Gy/25fx

Coverage 

area over 

prostate

SV

Whole pelvic 

±SV (if MRI+)

• SV

• 27% 

whole pelvic

• SV

• 19%

 whole pelvic

Whole pelvic

Adjuvant 

hormone 

therapy

ADT+Zytiga+Erleada

93% ADT

80% ADT

ADT

ADT

ADT

Duration of 

hormone 

therapy

6 mos.

2 yrs

6.3 mos.

4 mos.

28 mos.

2 yrs

Risk

VHR

78% HR

22% VHR

HR

HR

HR

≥20% LN risk

bRFS

89%

92%

87%

76%

88%

95%

HR=high risk VHR=very high risk SV=seminal vesicles bRFS=biochemical recurrence-free survival: PSA stayed lower than nadir+2.0 ng/ml

2.5 years of follow-up is too early to draw valid conclusions. We see that most of the trials had higher bRFS even with much longer follow-up; however, only AASUR recruited very high-risk patients exclusively. ICECAP has shown that only metastasis-free survival is a valid surrogate endpoint for overall survival. A trial on high-risk patients will have to run for 8-10 years to collect a sufficient number of metastases to draw valid conclusions, so we can only look at this as an early signal.

Treatment of Pelvic Lymph Nodes

We know that the time to be able to see the first few cancerous pelvic lymph nodes is often several years, so 2.5 years of follow-up tells us little. The newly approved PSMA PET scans will be able to rule out the larger metastases (>5 mm), but will never be able to find metastases smaller than that. Waiting for visibility to make the decision to treat is a bad idea. By the time some lymph nodes are large enough or rapidly growing, the risk of spread outside the pelvic lymph node drainage area increases, and the hope of a cure may vanish.

The PSMA PET/CT is nevertheless worthwhile. While a negative scan does not change the treatment decision, a positive scan may detect occult metastases or pelvic lymph nodes that may benefit from a higher spot dose and more intense or longer hormone therapy.

We rely on validated formulas to tell us the probability that there are microscopic pelvic lymph node metastases. Two of the popular formulas are the Roach Equation (discussed here) and the Yale Formula (discussed here).

There is a risk of overtreatment. Many high-risk patients will never require pelvic lymph node treatment, and we are awaiting evidence (RTOG 0924) that such treatment will improve survival. As we have seen, bRFS is improved.

However, the only risk is that toxicity will be higher when the whole pelvis is treated. Murthy et al. showed that even at higher doses of pelvic lymph node radiation, there was no increase in acute toxicity, late gastrointestinal toxicity, and no deterioration in patient-reported quality of life scores.

Arguably, 25 extra IMRT treatments to the pelvic lymph nodes represent a patient inconvenience over the 5 SBRT prostate-only treatments. In the UCLA and Sunnybrook high-risk SBRT trials (discussed here), the pelvic lymph nodes may be treated (to 25 Gy) within the same 5 treatments. So far, with limited follow-up, cancer control is high and toxicity is low.

Hormone therapy intensification

The DART 01.05 GICOR trial proved that long-term (28 months vs 4 months) ADT improves survival in high-risk patients even when treated with dose-escalated IMRT. Nabid et al. proved that 18 months is often as good as 36 months. AASUR suggests that by including both Zytiga and Erleada, the duration of hormone therapy can be shortened. But the sexual and hormone quality of life did diminish. This raises questions that can only be answered in an expanded randomized clinical trial:

  • Are all 3 medications (Zytiga, Erleada, and Lupron) necessary for the benefit? The ACIS trial found that adding Erleada increased radiographic progression-free survival in mCRPC patients. There was no such synergy found in adding Xtandi to Zytiga in this non-randomized trial.
  • Do they add much to Lupron alone if whole pelvic radiation is given?
  • Does Lupron alone for, say, 9 months, with whole-pelvic SBRT (as in the UCLA trial) afford the same benefit with less toxicity? And would Orgovyx instead of Lupron allow for earlier testosterone recovery?
  • Can genomics (Prolaris or Decipher of biopsy tissue) identify patients who might benefit from the combined hormone therapy?



Friday, April 30, 2021

First clinical trial of Lu-177-PSMA-617 in recurrent, hormone-sensitive men

While we expect only a few months of extra survival from the VISION trial of Lu-177-PSMA-617 in heavily pretreated, metastatic, castration-resistant men (see this link), we hope to get more out of the radiopharmaceutical if used earlier. Privé et al. reported the results of a pilot trial in 10 recurrent men treated with Lu-177-PSMA-617 at Radboud University in Nijmegen, The Netherlands. They were all:

  • Recurrent after prostatectomy ± salvage radiation (PSA>0.2 ng/ml) 
  • Rapid PSA doubling time (< 6 months)
  • Between 1-10 metastases detectable on a PSMA PET scan or USPIO MRI
  • At least 1 metastasis > 1 cm.
  • Unable to receive SBRT to metastases 
  • No visceral metastases 
  • Have not begun salvage ADT
  • Treated with a low dose (3 GBq) on day 1; second treatment (~6 GBq) after 8 weeks (compared to dose in VISION trial of 7.4 GBq in each of 4-6 cycles)

After 24 weeks of follow-up after Cycle 2:

  • 5 patients had PSA reduced by >50% (1 undetectable)
  • 2 patients had stable PSA
  • 3 patients had PSA progression
  • 6 patients had a radiographic response
  • 4 patients had radiographic progression
  • ADT-deferred survival was 9.5 months (median)
  • Those with lymph node only metastases had the best response
  • Those with any bone metastases had lesser response
After 2nd dose, comparing their 24-week PSA to their 12-week PSA:

  • PSA was continuing to decline in 3 patients
  • PSA was rising again in 6 patients

Side effects were mild (no grade 3) and transient:

  • fatigue in 7; nausea in 3
  • dry mouth (xerostomia) in 2

There are lots more questions than answers:
  • Would a higher dose and more treatments be more effective?
  • Would a higher dose and more treatments be more toxic?
  • Is it like Xofigo in that it's more effective with micrometatases? If so, would a combination with SBRT targeted at the larger metastases be more effective?
  • Since it was more effective on lymph nodes, would it make a good combination with Xofigo for patients who have both lymph node and bone metastases? (See also Th-227-PSMA)
  • Because there seems to be a continued abscopal effect for some patients, would combining it with Provenge be optimal?
  • Would pretreatment with ADT or a new anti-androgen (Xtandi, Erleada or Nubeqa) increase expression of PSMA, and increase radiosensitivity?
  • Can we predict who will benefit?
  • Use in other patient populations remains to be explored: high-risk, newly diagnosed metastatic, castration-resistant but chemo-naive. Optimal sequencing with other therapies remains to be explored.