Background: Approximately 10-15% of prostate cancer (PCa) patients (pts) have a pathogenic germline variant (PGV). Identification of a PGV has important implications affecting decisions regarding cancer screening, treatment selection, and family cascade testing. There exists limited data documenting real world recommendations post germline genetic testing (GGT). This study was designed to collect clinician reported outcomes from PCa pts who underwent GGT. Methods: An IRB-approved, nationwide, prospective registry recruited unselected PCa pts from 15 community and academic urology practices. Pts underwent an 84-gene panel test, with clinical outcomes collected via clinician-completed case report forms > 1-month post GGT. Statistical significance was determined by two-tailed Fisher’s exact test. Results: 982 predominantly white (75.9%), non-metastatic (80.7%) males with PCa were recruited; 56.9% met National Comprehensive Cancer Network (NCCN) GGT criteria. Average age was 65.3 years at PCa diagnosis. PGVs, most commonly CHEK2 (17) and BRCA2 (10), were identified in 100 (10.2%) pts; 34 (34%) of these did not meet NCCN GGT criteria. Among PGV positive pts, 241 recommendations were made (Table). They were more likely to have changes to treatment (p < 0.0001), follow up (p < 0.0001) and cascade testing recommendations (p < 0.0001) than those with negative/variant of uncertain significance (VUS) results. There were no significant differences in changes to treatment (p = 0.4471) or follow up (p = 0.861) for pts who met NCCN criteria versus those who did not. 7 pts with PGVs received targeted therapy or were referred to a clinical trial. 5 pts with VUS results were also referred to a clinical trial. Among these 12 pts, 6 (50%, 2 CHEK2 PGV, 1 ATM PGV, 1 VUS each ATM, BLM, CHEK2) did not meet NCCN GGT criteria. Referral to a genetic counselor was the most common follow up recommendation for those with PGV (38 patients, 38%) and VUS results (66, 13.7%). The most commonly reported impact to health outcomes for those with negative results was knowledge/reassurance (38, 7.88%). Conclusions: This study showed that GGT did influence PCa pts care. Appropriately, pts with PGVs received a greater number of recommendations for relatives, changes to follow up and treatment.

GC, genetic counseling; GGT, germline genetic testing; pt(s), patient(s); VUS, variant of uncertain significance.