External beam radiotherapy and androgen deprivation therapy after radical prostatectomy may reduce mortality risk among men with high-risk prostate cancer, according to study results published in JAMA Oncology.
Men with Gleason score 9 or 10 prostate cancer who underwent this treatment experienced similar rates of prostate cancer-specific mortality and all-cause mortality as men who underwent external beam radiotherapy, brachytherapy and ADT.
“In many cases when cancer recurs, radiation and hormone therapy are recommended, but our findings indicate that the best survival outcomes can be achieved by implementing these therapies directly after surgery and not waiting for the cancer to recur,” Anthony Victor D’Amico, MD, PhD, chief of radiation oncology at Brigham and Women’s Hospital, said in a press release. “[Although] more than 75% of men in this study had risk factors for recurrence following surgery for which radiation and hormone therapy could have been recommended, only one-third received those treatments.”
Researchers analyzed 639 men (mean age, 65.8 years) who received treatment for clinical T1-4, Gleason score 9 to10 prostate cancer between 1992 and 2013. Among them, 83.4% (n = 533) had no comorbidity, 15.8% (n = 101) had minimal comorbidity and 0.8% (n = 5) had moderate comorbidity.
Eighty of the men underwent external beam radiotherapy, brachytherapy and ADT at Chicago Prostate Cancer Center. The other 559 men underwent radical prostatectomy and pelvic lymph node dissection at Martini-Klinik Prostate Cancer Center.
Among those who underwent radical prostatectomy, 88 (15.7%) received adjuvant external beam radiotherapy, 49 (8.8%) received ADT and 50 (8.9%) received both therapies.
Follow-up concluded in October 2017.
After median follow-ups of 5.51 years (interquartile range [IQR], 2.19-6.95) for the radiotherapy, brachytherapy and ADT group and 4.78 years (IQR, 4.01-6.05) for the radical prostatectomy, 161 men had died, including 106 who died of prostate cancer.
Researchers reported no significant difference between groups in the risk for prostate cancer-specific mortality (adjusted HR = 1.33; 95% CI, 0.49-3.64; plausibility index value for equivalence of risk, 76.75%) or all-cause mortality (adjusted HR = 0.8; 95% CI, 0.36-1.81; plausibility for equivalence of risk, 77.97%). Plausibility indexes for all other treatment comparisons were less than 63%.
Researchers acknowledged the study was limited by a lack of randomization.
“The strength of our study is the adjustment for the use of adjuvant and salvage therapies using time-dependent covariates, enabling a comparison of [the two treatments] with respect to the endpoints of prostate cancer-specific mortality risk and all-cause mortality risk,” the researchers wrote. – by John DeRosier
Disclosures: The authors report no relevant financial disclosures.