Earlier this
month, we looked at the evidence of benefit for adding chemo to radiation
therapy for high-risk prostate cancer (see “Docetaxel with radiation in prostate cancer treatment”).
Early results of RTOG 0521 showed only a modest benefit in the
short term. Would longer term follow up reveal a greater benefit?
We now have a ten-year update of RTOG 9902, a clinical trial begun in 2000 and
closed to accrual in 2004 because of excess toxicity. Although the study ended before it met
its accrual goal, patients continued to be tracked. The study protocol included:
- · 380 high-risk patients were randomized to two arms
- · High Risk:
o Gleason score≥7 and PSA from 20 to 100
ng/ml or
o Gleason score≥8 and stage≥T2
- · Two arms:
o Chemo + ADT + RT
o ADT + RT
- · Chemo: Paclitaxel + Estramustine + Etoposide
- · ADT: LHRH agonist (24 months) + anti-androgen (4 months), both begun 2 months before RT
- · RT: 70 Gy
The ten-year
results were as follows:
- · Overall survival: 63% with chemo, 65% without chemo (no sig. difference)
- · Local progression: 7% with chemo, 11% without chemo (no sig. difference)
- · Distant metastases: 14% with chemo, 16% without chemo (no sig. difference)
- · Disease-free survival: 26% with chemo, 22% without chemo (no sig. difference)
Before we write
off adjuvant chemo with radiation entirely, we must acknowledge that the
clinical trial was begun before docetaxel became available. Docetaxel is far
more effective and far less toxic than the chemo used in this study. They also
used a radiation dose of only 70 Gy, which we now know to be inadequate for
high-risk patients. So far, all we can conclude is that we don’t have enough
evidence to change the standard of care to include chemo with radiation.
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