In a study reported in the Journal of Clinical Oncology, Derya Tilki, MD, and colleagues identified a prostate-specific antigen (PSA) level cutpoint, above which initiation of salvage radiation therapy after radical prostatectomy was associated with an increased risk of all-cause mortality in patients with prostate cancer.
Study Details
The study cohort consisted of 25,551 patients with pT2-4N0 or NXM0 disease consecutively treated between June 1990 and June 2020 at the University Hospital Hamburg-Eppendorf (n = 24,345) or the University of California, San Francisco (n = 1,206). Patients could have at most one high-risk factor—ie, pT3/4 disease or a Gleason score between 8 and 10. Cox regression analysis was used to determine whether a significant increase in all-cause mortality risk was observed when salvage radiation therapy was delivered above a particular PSA level, beginning at 0.10 ng/mL and in 0.05 increments up to 0.50 ng/mL vs at or below that level. The model was adjusted for age at and year of radical prostatectomy, established prostate cancer prognostic factors, institution, and time-dependent use of androgen-deprivation therapy.
Among patients with at most one high-risk factor, initiating salvage radiation therapy above a PSA level of 0.25 ng/mL was associated with increased all-cause mortality risk.— Derya Tilki, MD, and colleagues
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Key Findings
Median follow-up was 6 years.
Patients who received salvage radiation therapy at a PSA level of > 0.25 ng/mL had a significantly higher risk of all-cause mortality (adjusted hazard ratio [aHR] = 1.49; 95% confidence interval [CI] = 1.11–2.00, P =.008) vs those who received salvage radiation therapy at PSA levels of ≤ 0.25 ng/mL.
Patients who received salvage radiation therapy at a PSA level of > 0.25 ng/mL had a numerically elevated risk of prostate cancer–specific mortality (aHR = 1.43, 95% CI = 0.80–2.55) vs those who received salvage radiation therapy at PSA levels of ≤ 0.25 ng/mL.
Elevated risk of all-cause mortality was significant for all PSA cutpoints above 0.25 ng/mL through 0.50 ng/mL. At the 0.50 ng/mL cutpoint, the adjusted hazard ratio was 1.61 (95% CI = 1.21–2.14, P = .001).
Adjusted hazard ratios for PSA cutpoints of 0.20, 0.15, and 0.10 were 1.28, 1.11, and 0.88, respectively, with none being statistically significant.
The investigators concluded: “Among patients with at most one high-risk factor, initiating salvage radiation therapy above a PSA level of 0.25 ng/mL was associated with increased all-cause mortality risk.”
Anthony V. D’Amico, MD, PhD, of the Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the UCSF Goldberg-Benioff Program in Translational Cancer Biology. For full disclosures of the study authors, visit ascopubs.org.
