In a U.S. retrospective cohort study reported in JAMA Network Open, Sebastian et al found that treatment at a high-volume radiation facility was associated with improved overall survival among men with very high–risk prostate cancer receiving curative-intent radiotherapy with androgen-deprivation therapy.
The study focused on data from the National Cancer Database on patients with nonmetastatic very high–risk prostate cancer (clinical T3b–T4 category, primary Gleason pattern 5, > 4 cores with grade group 4–5, and/or 2–3 high-risk features) treated with radiotherapy and androgen-deprivation therapy between January 2004 and December 2016. Average cumulative facility volume (ACFV) was defined as the total number of prostate radiotherapy cases at an individual patient’s treatment facility from 2004 until the year of his diagnosis.
Key Findings
A total of 25,219 men with very high–risk prostate cancer were identified; of them, 6,438 (25.5%) were treated at high-ACFV facilities. The median ACFV was 56 patients (interquartile range = 33–90 patients) treated per year; the optimal cutoff for high ACFV was 89 patients treated per year. Median follow-up was 57.4 months (95% confidence interval [CI] = 56.7–58.1 months).
Median overall survival was 123.4 months (95% CI = 116.6–127.4 months) among patients treated at high-ACFV facilities vs 109.0 months (95% CI = 106.5–111.2 months) among those treated at low-ACFV facilities (P < .001). On multivariate analysis, treatment at a high ACFV facility was associated with a reduced risk of mortality (hazard ratio [HR] = 0.89, 95% CI = 0.84–0.95, P < .001). Estimated 10-year overall survival was 51.5% (95% CI = 49.1%–53.8%) for patients treated at high-ACFV facilities vs 43.9% (95% CI = 42.4%–45.4%) among those treated at low-ACFV facilities.
On inverse probability score weighting–adjusted multivariate analysis, treatment at a high-ACFV facility remained associated with improved overall survival (HR = 0.90, 95% CI = 0.85–0.95, P < .001).
The investigators concluded: “In this cohort study of patients with [very high–risk] prostate cancer who underwent definitive radiotherapy and androgen-deprivation therapy, facility case volume was independently associated with longer [overall survival]. Further studies are needed to identify which factors unique to high-volume centers may be responsible for this benefit.”
Sagar A. Patel, MD, of the Department of Radiation Oncology, Winship Cancer Institute at Emory University, Atlanta, is the corresponding author of the JAMA Network Open article.
Disclosure: The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit jamanetwork.com.
