Prophylactic whole pelvis radiation therapy (WPRT) may improve survival in patients with unfavorable intermediate- and high-risk prostate cancer who have higher lymph node (LN) risk scores and Gleason grade, a new study finds.
Investigators compared survival outcomes among 15,175 patients treated with prostate-only external-beam radiation therapy and 13,549 men treated with WPRT from the 2008-2015 National Cancer Database. They calculated each patient’s risk for LN involvement using the Memorial Sloan Kettering Cancer Center (MSKCC) nomogram.
Every 1% increase in risk of LN involvement was significantly associated with a 1% increase in risk for all-cause mortality, Neal Andruska MD, PhD, of Washington University School of Medicine, Saint Louis, Missouri, and colleagues reported in The Journal of Urology. WPRT was significantly associated with a 13% and 7% reduced risk for death in men with Gleason 9-10 disease and an MSKCC risk for LN involvement of 10% or higher, respectively.
Prostate-only RT was delivered at a dose range of 72-86.4 Gy and WPRT was delivered at a lower dose range of 40-50.4 Gy. The survival benefit, however, was independent of radiation dose and androgen deprivation therapy.
These real-world findings complement results from the recent POP-RT randomized trial. In the current study, men had intermediate- to high-risk prostate cancer based on conventional imaging, whereas in the POP-RT trial, men had high to very high-risk disease based mostly on PET/CT-staging.
“Our study adds to the literature by extending the results of the POP-RT trial to show an OS benefit associated with WPRT in patients staged with conventional imaging at high risk of LN involvement,” Dr Andruska’s team wrote.
WPRT utilization increased from 2008 to 2015 predominantly among patients with more severe prostate cancer, the investigators noted.
Andruska N, Fischer-Valuck BW, Waters M, et al. Survival outcomes in men with unfavorable intermediate-risk and high-risk prostate cancer treated with prostate-only versus whole pelvic radiation therapy. J Urol. Published online January 20, 2022. doi:10.1097/JU.0000000000002455