Determining an appropriate course of androgen-deprivation therapy in patients with prostate cancer is complex. For patients with high-risk features, 4 to 6 months of androgen-deprivation therapy helps, but 28 to 36 months is better in terms of disease control and overall survival. In the study by Nabid et al, an intermediate-length 18-month course of androgen-deprivation therapy was associated with reduced toxicity and impact on patient quality of life compared to a 36-month course.
The other unanswered question is, how much androgen-deprivation therapy is needed when dose-escalated radiation therapy is given, if needed at all? Previous studies for intermediate- and high-risk patients all used lower radiation doses and so the waters have been muddied somewhat in terms of our ability to interpret the outcomes of these studies in the modern era. The study by Zapatero et al showed us that for patients receiving high-dose radiotherapy, hormone therapy is still advantageous and longer courses were still the best in patients with the highest-risk cancers.
How Long Is Long Enough?
The question is then how long is long enough? It is not clear yet that 18 months is enough, but 36 months may indeed be too long for some patients, especially given the impacts on patient-reported quality of life.
Ideally, we need to offer the shortest course of hormone therapy to our patients that will still maximally impact their chance for cure while maintaining adequate quality of life. We need to get more granular in our approach to defining risk so that we know which patients can get by with shorter courses of androgen-deprivation therapy and identify which patients may need longer durations. Currently, we end up both overtreating and undertreating some patients, because we still don’t have a perfect way to predict outcome. Ongoing work in the area of molecular biomarkers will no doubt help us with these difficult treatment decisions in the future. ■
Disclosure: Dr. Gray reported no potential conflicts of interest.
Dr. Gray is a radiation oncologist at Massachusetts General Hospital in Boston.
