EBRT with 2 years of ADT better than 4 months in patients treated for locally advanced prostate cancer

It will come as no surprise that long-term ADT improved outcomes among men treated for locally advanced prostate cancer with external beam radiation. While this study is largely irrelevant now because a more recent study, DART 01/05 (discussed here), proved much the same thing with dose-escalation, this study also included pelvic lymph node treatment and has a median of 20 years of follow up.

The final results of RTOG 0902 were reported at the recent ASTRO meeting by Lawton et al. and in a news release. In this multi-institutional study, 1,992 patients were treated between 1992 and 1995. They were all high risk (T2c-T4) with no detectable distant metastases and PSA<150. All patients ere treated according to the following protocol:

• ·      44-46 Gy to the pelvic lymph nodes
• ·      65-70 Gy to the prostate
• ·      The short-term ADT group (STADT) received 4 months of flutamide and goserelin, starting 2 months before EBRT.
• ·      The long-term ADT group (LTADT) received 24 additional months of goserelin.

At 15 years after treatment:

• ·      Disease-free survival was 16% for the LTADT group vs. 10% for the STADT group, and was statistically significant.
• ·      PSA increase was 45% for the LTADT group vs. 61% for the STADT group, and was statistically significant.
• ·      Local progression was 13% for the LTADT group vs. 23% for the STADT group, and was statistically significant.
• ·      Distant metastases rate was 17% for the LTADT group vs. 26% for the STADT group, and was statistically significant.
• ·      Disease-specific survival was 10% higher for the LTADT group vs. the STADT group, and was statistically significant.
• ·      Overall survival was 30% for the LTADT group vs. 27% for the STADT group, and was not statistically significant.
• ·      No difference in urinary toxicity and minimal difference in bowel toxicity between the two groups.

While all the survival numbers are very low in both groups, it should be recalled that the radiation dose received back then was well below the dose now considered curative. Also, most of such men would now be diagnosed at a much earlier stage of disease progression. There was a clear benefit to long-term compared to short-term androgen suppression, and DART 01/05 proved that the benefit was still true with dose escalation in high-risk patients.