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Top Line: What is the ideal sequence of radiation and short-course ADT for prostate cancer?

The Study: Two randomized trials have asked this question (Ottawa 0101 and RTOG 9413). Both were suggestive (but not conclusive) that adjuvant ADT might be superior to neoadjuvant. Here we have publication of a patient-level meta-analysis of both trials. In the Ottawa trial, everyone had 2 months of ADT during RT that was either preceded or followed by 4 months of ADT. In 9413, one arm received 2 months neoadjuvant and 2 months concurrent ADT while the other arm received 4 months adjuvant ADT. Over 1000 patients were included in the meta-analysis, and after 15 years, there was a 10.8 month improvement in the restricted mean survival time for progression. The 15-year PFS rate was also improved from 29 → 36%, as were the rates of biochemical failure and distant metastasis. There was no difference in overall survival or prostate cancer mortality. Lastly, there was no difference in treatment toxicity based on ADT sequence. The somewhat unique aspect of this question is that our choice of sequencing ADT with radiation has no impact on the duration of ADT. So, unlike many therapeutic options we consider, this one changes nothing about the treatment delivered--simply the timing of administration.

TBL: Ideally, radiation and androgen deprivation should begin simultaneously and ADT be continued adjuvantly as there is no difference in toxicity and potentially significant improvements in treatment outcomes. | Spratt, J Clin Oncol 2020