Prostate-only Versus Whole-pelvis Radiation with or Without a Brachytherapy Boost for Gleason Grade Group 5 Prostate Cancer: A Retrospective Analysis

• Published in: European urology 2020-01, Vol.77 (1), p.3-10
• Main Authors: Sandler, Kiri A., Cook, Ryan R., Ciezki, Jay P., Ross, Ashley E., Pomerantz, Mark M., Nguyen, Paul L., Shaikh, Talha, Tran, Phuoc T., Stock, Richard G., Merrick, Gregory S., Demanes, David Jeffrey, Spratt, Daniel E., Abu-Isa, Eyad I., Wedde, Trude B., Lilleby, Wolfgang, Krauss, Daniel J., Shaw, Grace K., Alam, Ridwan, Reddy, Chandana A., Song, Daniel Y., Klein, Eric A., Stephenson, Andrew J., Tosoian, Jeffrey J., Hegde, John V., Yoo, Sun Mi, Fiano, Ryan, D’Amico, Anthony V., Nickols, Nicholas G., Aronson, William J., Sadeghi, Ahmad, Greco, Stephen C., Deville, Curtiland, McNutt, Todd, DeWeese, Theodore L., Reiter, Robert E., Said, Jonathan W., Steinberg, Michael L., Horwitz, Eric M., Kupelian, Patrick A., King, Christopher R., Kishan, Amar U.
• Format: Article
• Language: English
• Subjects: Aged; Brachytherapy; Gleason grade group 5; Hemibody Irradiation; Humans; Male; Neoplasm Grading; Pelvis; Prostate; Prostate cancer; Prostatic Neoplasms - mortality; Prostatic Neoplasms - pathology; Prostatic Neoplasms - radiotherapy; Radiation therapy; Retrospective Studies; Survival Rate; Whole-pelvis irradiation
• ISSN: 0302-2838; 1873-7560
• DOI: 10.1016/j.eururo.2019.03.022

The role of elective whole-pelvis radiotherapy (WPRT) remains controversial. Few studies have investigated it in Gleason grade group (GG) 5 prostate cancer (PCa), known to have a high risk of nodal metastases. To assess the impact of WPRT on patients with GG 5 PCa treated with external-beam radiotherapy (EBRT) or EBRT with a brachytherapy boost (EBRT+BT). We identified 1170 patients with biopsy-proven GG 5 PCa from 11 centers in the United States and one in Norway treated between 2000 and 2013 (734 with EBRT and 436 with EBRT+BT). Biochemical recurrence-free survival (bRFS), distant metastasis-free survival (DMFS), and prostate cancer-specific survival (PCSS) were compared using Cox proportional hazards models with propensity score adjustment. A total of 299 EBRT patients (41%) and 320 EBRT+BT patients (73%) received WPRT. The adjusted 5-yr bRFS rates with WPRT in the EBRT and EBRT+BT groups were 66% and 88%, respectively. Without WPRT, these rates for the EBRT and EBRT+BT groups were 58% and 78%, respectively. The median follow-up was 5.6yr. WPRT was associated with improved bRFS among patients treated with EBRT+BT (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.2–0.9, p=0.02), but no evidence for improvement was found in those treated with EBRT (HR 0.8, 95% CI 0.6–1.2, p=0.4). WPRT was not significantly associated with improved DMFS or PCSS in the EBRT group (HR 1.1, 95% CI 0.7–1.7, p=0.8 for DMFS and HR 0.7, 95% CI 0.4–1.1, p=0.1 for PCSS), or in the EBRT+BT group (HR 0.6, 95% CI 0.3–1.4, p=0.2 for DMFS and HR 0.5 95% CI 0.2–1.2, p=0.1 for PCSS). WPRT was not associated with improved PCSS or DMFS in patients with GG 5 PCa who received either EBRT or EBRT+BT. However, WPRT was associated with a significant improvement in bRFS among patients receiving EBRT+BT. Strategies to optimize WPRT, potentially with the use of advanced imaging techniques to identify occult nodal disease, are warranted. When men with a high Gleason grade prostate cancer receive radiation with external radiation and brachytherapy, the addition of radiation to the pelvis results in a longer duration of prostate-specific antigen control. However, we did not find a difference in their survival from prostate cancer or in their survival without metastatic disease. We also did not find a benefit for radiation to the pelvis in men who received radiation without brachytherapy. In this multi-institutional observational study, whole-pelvis radiation therapy was found to improve biochemic