Thursday, August 25, 2016

Trends in the use of radiation for primary therapy

Two separate database analyses have now reported an increasing trend in adoption of SBRT, while brachytherapy use has been declining.

In an analysis of the National Cancer Data Base, Baker et al. reported that use of SBRT increased from <1% in 2004 (it was first used for prostate cancer in 2003) to 8.8% of low-risk patients treated at academic centers in 2012. Similarly, Halpern et al., in an analysis of the SEER/Medicare database,  found that SBRT was the fastest-growing of all radiation therapies between 2004 and 2011, but it only accounted for 1.6% of all men treated with radiation in that database. They also found that adoption was highest among low-risk patients: 54% of those using it had a Gleason score of 6. The median cost was $27,145.

Proton beam therapy use also increased. It accounted for 2.3% of all radiation therapy utilization. Half of those using it had a Gleason score of 6. It had the highest cost of all radiation therapies at $54,706.

Brachytherapy use, on the other hand, is on the decline. It accounted for 28% of all primary radiation therapies. Compared to other radiation therapies, a higher proportion of those utilizing it had a low Gleason score: 64.2% of those utilizing it had a Gleason score of 6. It was the lowest cost of all radiation therapies at a median cost of $17,183.

It is unclear how combination therapies of EBRT with a brachytherapy boost were counted in The SEER/Medicare database analysis. Orio et al. reported that in their analysis of the National Cancer Data Base, use of such combination therapy in intermediate and high-risk patients declined markedly between 2004 and 2012. They found that among intermediate and high-risk patients, 66% were treated with EBRT alone, 20% were treated with brachytherapy alone, and only 14% were treated with the combination. Use of combination therapy declined from 15% to 8% in academic centers, and from 19% to 11% in non-academic centers. We will have to see if the results of the ASCENDE-RT randomized clinical trial last year (discussed here) reverses this trend.

IMRT took the lion’s share of all radiation therapies at 68.1%. Relative to the other radiation therapies, it was most likely to be used by patients with higher Gleason scores: almost two-thirds of patients using it had Gleason scores of 7 or greater. I suspect that it continues to be the treatment of choice in older patients, who tend to have more progressed prostate cancer at the time of diagnosis. Next to proton therapy, it was most expensive, costing a median of $37,090. Hypofractionation may be able to cut the cost if it is widely adopted.

It should be noted that the high rate of utilization of brachytherapy, SBRT and proton therapy among low risk patients has historical roots. Those therapies were originally tried in low risk patients before we had results from Active Surveillance trials. While proton therapy and brachytherapy are given as boosts to IMRT, their use as monotherapies has not been established in intermediate and high-risk patients. SBRT, as both a boost and a monotherapy, is in trials for the higher risk categories, but many institutions still do not offer it for that purpose, and insurance may be reluctant to cover it.

It is sad to witness the decline in brachytherapy utilization, especially considering it is the lowest cost alternative. But that works to its detriment as well: new practitioners are not attracted to its relatively low profit potential. With the passing of Peter Grimm this year, it has lost one of its greatest proponents. The generation of brachytherapists who developed its modern techniques at the University of Washington Seattle have mostly dispersed and some have retired. It is a very specialized therapy, requiring years of practice to get superlative results. I expect we will continue to lose our best practitioners, and patients will find it increasingly difficult to find.

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