SAN DIEGO—While the addition of androgen deprivation therapy to radiation therapy improves survival in patients with intermediate- and high-risk prostate cancer, it remained unknown whether combined androgen blockade with a gonadotropin-releasing hormone agonist and a nonsteroidal antiandrogen could further improve survival.
A study published in the Journal of the National Comprehensive Cancer Network used the VA Informatics and Computing Infrastructure to evaluate patients with intermediate- and high-risk PCa diagnosed in 2001 through 2015 who underwent RT with either GnRH-A alone or CAB.1
University of California San Diego-led researchers also determined associations between CAB and prostate cancer-specific mortality and overall survival. For a positive control, the effect of long-term vs. short-term GnRH-A therapy was tested.
In the cohort were 8,423 men – 4,529 treated with GnRH-A and 3,894 with CAB, with a median follow-up of 5.9 years. During the study period, 1,861 patients died, including 349 from prostate cancer.
The authors calculated the unadjusted cumulative incidences of PCSM at 10 years at 5.9% and 6.9% for those receiving GnRH-A and CAB, respectively (P=0.16).
“Compared with GnRH-A alone, CAB was not associated with a significant difference in covariate-adjusted PCSM (subdistribution hazard ratio [SHR], 1.05; 95% CI, 0.85-1.30) or OS (hazard ratio, 1.02; 95% CI, 0.93-1.12),” the researchers pointed out. “For high-risk patients, long-term vs. short-term GnRH-A therapy was associated with improved PCSM (SHR, 0.74; 95% CI, 0.57-0.95) and OS (SHR, 0.82; 95% CI, 0.73-0.93).”
- Vitzthum LK, Straka C, Sarkar RR, McKay R, Randall JM, Sandhu A, Murphy JD, Rose BS. Combined Androgen Blockade in Localized Prostate Cancer Treated With Definitive Radiation Therapy. J Natl Compr Canc Netw. 2019 Dec;17(12):1497-1504. doi: 10.6004/jnccn.2019.7335. PubMed PMID: 31805534.