In the last couple of years, there have been some changes in the way intermediate risk PC is categorized. There is general agreement now that "favorable intermediate risk" PC like yours (no GS higher than 3+4 and less than half the cores positive) has a similar prognosis and ought to be treated the same way as "low risk" PC.
The following is from my review of the subject of adding ADT to EBRT. Go to the the article for links to the actual published studies in peer-reviewed journals.
My review said...
Favorable vs. Unfavorable Intermediate Risk
In an earlier article, we noted that Dr. D’Amico raised a caution that the results may look very different if the intermediate risk men were divided into favorable and unfavorable groups. It may be that with further follow-up time, significant differences will appear among the intermediate risk men, and particularly among those with unfavorable features. In a retrospective study by Castle et al. where intermediate risk men were divided into favorable or unfavorable intermediate risk, favorable risk patients had no discernable benefit from the addition of ADT. Unfavorable intermediate risk patients had significantly higher 5-yr freedom from failure if they also received ADT, 74% vs. 94%, respectively. Similarly, Edelman et al. found that ADT combined beneficially with RT only in intermediate risk patients with GS 4+3, more than 50% positive cores, or multiple intermediate risk factors.
Another retrospective study by Keane et al. confirming that finding was presented at the recent Genitourinary Conference. They analyzed the oncological outcomes of 2,668 intermediate risk men (71% favorable, 29% unfavorable) treated between 1997 and 2013 with dose-escalated RT and with and without adjuvant ADT (median 4 months). After a median follow-up of 7.8 years, they found that there was a significant amelioration of the risk of prostate cancer-specific mortality among the unfavorable risk patients who also received ADT, but adding ADT did not make a difference to prostate cancer-specific mortality in those men categorized as favorable intermediate risk.
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