Whole-d it right there.
The Study: The RTOG 9413 was designed in the early 90s to ask two questions about optimal definitive radiation treatment for higher risk prostate cancer: timing of ADT and utility of including elective nodal regions. If you’re familiar with today’s standard of care, you’re familiar with the winning arm from this 2x2 design—neoadjuvant ADT followed by radiation to the prostate and elective nodes. As a reminder, 1322 men were enrolled with clinically node-negative prostate cancer with an algorithm-indicated risk of microscopic nodal disease of at least 15%. After a median follow-up of 9 years (15 years for those still living), we now have final long-term results. And they’re less than satisfying. Looks like the winner of the primary endpoint of progression free survival (PFS) now goes to...the exact opposite. PFS at 10 years was numerically highest with adjuvant ADT without nodal coverage. WTF. According to the supplementary material, trends for biochemical control and survival follow the same patterns. The clearest result? Late grade 3 or higher GI toxicity was more than doubled with neoadjuvant ADT and elective nodal coverage than in any other arm. The lengthy discussion should contain your fill of speculations on why all this was. To paraphrase (in less kind words), maybe all this doesn’t even matter considering radiation doses and techniques are completely different now than in 1993.
Bottom Line: Long-term results of the landmark RTOG 9413 demonstrate we may have chosen the wrong standard of care for higher risk prostate cancer, but maybe RTOG 0924 can clear things up in 2031...when we're all using SBRT. | Roach, Lancet Oncol 2018