Germline genetic testing for prostate cancer: Ordering trends in the era of expanded hereditary cancer screening recommendations.

Purpose: The availability of targeted therapies for advanced prostate cancer led to the expansion of national guidelines recommending germline genetic testing. The aim of this study was to describe recent trends in germline test ordering patterns for patients with prostate cancer.

Materials and methods: A retrospective cohort analysis of patients with prostate cancer who underwent germline testing through a single commercial laboratory (Invitae Corporation) between 2015-2020 was performed. Ordering trends between provider medical specialties were compared. Our primary hypothesis was that the proportion of tests ordered by urologists would increase over time.

Results: In total, 17,256 prostate cancer patients underwent germline genetic testing; 14,400 patients had an ordering provider with an associated medical specialty and were included in the final comparison cohort. Total prostate cancer patients undergoing germline testing increased quarterly from 21 in Q2 of 2015 to 1,509 in Q3 of 2020. The proportion of tests ordered by urologists increased from 0% in Q2 2015 to 8.3% in Q3 2020 (P < 0.001). Compared to medical genetics, medical oncology, and other specialties, urology ordered more tests for patients under 70 years old (66% vs 51%-55%, P <0.004) and for patients who reported negative family history (25% vs 12%-20%, P = 0.012).

Conclusions: As awareness and indications for germline testing continue to expand, aggregate ordering volume is increasing, and urologists are becoming more involved in facilitating testing. This highlights the continued importance of educating urologists on the indications for and implications of germline genetic testing, as well as providing tools to support implementation.