Inherited Germline Cancer Susceptibility Gene Variants in Individuals with Non-Muscle-Invasive Bladder Cancer.

Overview

abstract

PURPOSE: Identification of inherited germline variants can guide personalized cancer screening, prevention, and treatment. Pathogenic and likely pathogenic (P/LP) germline variants in cancer predisposition genes are frequent among patients with locally advanced or metastatic urothelial carcinoma, but their prevalence and significance in patients with non-muscle invasive bladder cancer (NMIBC), the most common form of urothelial carcinoma, is understudied. EXPERIMENTAL DESIGN: Germline analysis was conducted on paired tumor/normal sequencing results from two distinct cohorts of patients initially diagnosed with NMIBC. Associations between clinicopathologic features and clinical outcomes with the presence of P/LP germline variants in ≥76 hereditary cancer predisposition genes were analyzed. RESULTS: A similar frequency of P/LP germline variants were seen in our two NMIBC cohorts (12% [12/99] vs. 8.7% [10/115], p=0.4). In the combined analysis, P/LP germline variants were found only in patients with high-grade NMIBC (22/163), but none of the 46 patients with low-grade NMIBC (13.5% vs. 0%, p=0.005). Fifteen (9.2%) patients with high-grade NMIBC had P/LP variants in DNA damage response (DDR) genes, most within the nucleotide excision repair (ERCC2/3) and homologous recombination repair (BRCA1, NBN, RAD50) pathways. Contrary to prior reports in NMIBC patients not receiving BCG, P/LP germline variants were not associated with worse recurrence-free or progression-free survival in patients treated with BCG. CONCLUSIONS: Our results support offering germline counseling and testing for all patients with high-grade bladder cancer, regardless of the initial tumor stage. Therapeutic strategies that target impaired DNA repair may benefit patients with high-grade NMIBC.