The study adds to a growing body of literature now suggesting that ADT in combination with EBRT is not indicated for the low-risk patient.
The study randomized nearly 2,000 men to receive EBRT alone (66.6 or 68.4 Gy) or EBRT in combination with 4 months of ADT, started 2 months prior to radiation. The study showed a significant improvement in 10-year overall survival favoring the combination group (62%) versus the EBRT-alone group (57%). Even more interesting was the finding in the risk-stratified subset analysis that the only group shown to benefit from the addition of short-course ADT was the intermediate-risk group. No benefit was noted among the low-risk prostate cancer patients.
Although the study is one of the longest clinical trials in prostate cancer ever completed, it suffered from the use of inadequate doses of radiation therapy compared with that used in more contemporary series of radiation therapy.
Finally, we need to educate our radiation therapy colleagues as these studies mature. Surveys continue to report that 25% to 30% of low-risk patients with localized prostate cancer receive EBRT with ADT in lieu of EBRT alone, despite the paucity of data suggesting a benefit (Int J Radiat Oncol Biol Phys 2004; 59:1053-61; and J Clin Oncol 2004; 22:2141-9). The data for patients on both ends of the spectrum appear quite clear: no benefit to the addition of any ADT for the low-risk group, and 2 to 3 years of ADT plus EBRT is superior to EBRT alone for the high-risk group. More data are needed to help clarify the use of ADT in the intermediate-risk group.
Dr. Thrasher, a member of the Urology Times Editorial Council, is professor and chair of urology, University of Kansas Medical Center, Kansas City.