"I believe the study by Nabid and colleagues will help inform practice,” said formal discussant D. Andrew Loblaw, MD, radiation oncologist at Odette Cancer Institute, Sunnybrook Health Sciences Centre, Toronto, Canada.
“At a median follow up of 6.3 years, short-term androgen-deprivation therapy plus radiation achieved clinically and statistically significant improvements in biochemical outcomes but no difference in overall survival,” Dr. Loblaw said.
Dr. Loblaw said he didn’t see much difference between arms 1 and 2. “The extra 6 Gy in arm 2 may introduce more side effects,” he added.
“Many of us practicing have been offering dose-escalated external-beam radiation therapy for over a decade based on randomized data. While there have been other randomized studies showing that short-term androgen-deprivation therapy plus radiation [ie, 66–70 Gy] improved outcomes compared to radiation alone, the doses used in those trials were historic. We believed that dose escalation with radiotherapy alone [ie, 76–78 Gy] was probably equal to adding short-term androgen-deprivation therapy to lower radiation therapy doses.
“But Nabid’s study shows us that 70 Gy+ short-term androgen-deprivation therapy is superior to 76 Gy. Also, we know that 66 Gy+ short-term androgen-deprivation therapy improves overall survival [from RTOG 9408]. So I believe short-term androgen-deprivation therapy should be considered for all intermediate-risk patients,” Dr. Loblaw commented.
“The ASCENDE-RT trial then tells us the added value of a brachytherapy boost for intermediate-risk (and high-risk) patients getting short-term androgen-deprivation therapy. A brachytherapy boost significantly improves prostate-specific antigen control over 78 Gy,” he said. ■
Disclosure: Dr. Loblaw has received grants/research support from Sanofi and Paladin and honoraria from Amgen, AstraZeneca, Elekta, GE, Janssen, Paladin, and Sanofi, is on the advisory boards of Amgen, Astellas, Janssen, and Sanofi, and is associated with the financial groups TSRCC Radiation Oncology Associates and Atlas Global.
