Germline DNA damage repair variants and prognosis of patients with high-risk or metastatic prostate cancer

Abstract

Purpose: Deleterious germline variants in certain DNA repair genes are risk factors for developing aggressive prostate cancer. The objective was to quantify their prognostic impact after prostate cancer diagnosis. Methods: Men with prostate cancer, predominantly of European ancestry, were included from four cohorts with long-term follow-up. Pathogenic or likely pathogenic germline variants in 26 DNA repair genes were assessed in relation to metastasis-free survival in high-risk, localized prostate cancer and to overall survival in metastatic castration-sensitive prostate cancer (mCSPC) and metastatic castration-resistant prostate cancer (mCRPC). Results: Among 3,525 patients initially diagnosed with non-metastatic prostate cancer, 2,594 had high-risk localized prostate cancer, 429 mCSPC, and 502 mCRPC at inclusion. BRCA2 variant carriers did not have worse metastasis-free survival in high-risk localized prostate cancer (hazard ratio [HR] 1.01, 95% confidence interval [CI] 0.69, 1.46) or overall survival in mCSPC (HR 0.46, 95% CI 0.14, 1.45) or mCRPC (HR 0.60, 95% CI 0.31, 1.17) compared to non-carriers of DNA repair variants. Among 868 additional patients with de novo metastatic (M1) prostate cancer, BRCA2 variant carriers tended to have worse overall survival (HR 1.59, 95% CI 1.01, 2.51). BRCA2 prognostic associations were not explained by radiation, PARP inhibitor, or platinum therapy. Results for other genes were limited in precision because variants were less common. Conclusions: Among patients with high-risk or metastatic prostate cancer who were initially diagnosed with and treated for non-metastatic tumors, germline DNA repair variants in BRCA2 do not confer a substantially worse prognosis.