All together now.

Top Line: How do you sequence androgen deprivation therapy (ADT) with prostate radiation? 

The Study: Many wait to start radiation several months after ADT with the idea that the prostate volume can decrease by as much as 30%. That’s an important logistical point of radiation. But are there any disease-related outcomes related to starting ADT prior to radiation? This is less clear. Historically, there were arguments both for and against the radiosensitization of prostate cancer cells by ADT. The former argument—despite the extensive radiation biology knowledge of the 1990s—has proven more accurate as androgen receptor signaling promotes many oncogenic processes in cancer cells such as DNA repair. In this trial, 432 men receiving short-course androgen deprivation for 6 months were randomized to initiate ADT either 4 months prior to or concurrent with the start of radiation. At 10 years, the rate of biochemical recurrence-free survival was 80.5% for neoadjuvant/concurrent ADT and 87.4% for concurrent and adjuvant ADT  (HR 0.66; 95% CI 0.41-1.07). While that difference was not statistically significant, it raised our eyebrows. Importantly, there were no differences in treatment toxicity.

TBL: You may not be wrong to start ADT and prostate radiation at the same time. | Malone, J Clin Oncol 2019