Real-world Homologous Recombination Repair Mutation Testing in Metastatic Castration-Resistant Prostate Cancer in the USA, Europe and Japan

Lay abstract Metastatic castration-resistant prostate cancer (mCRPC) is cancer that has spread beyond the prostate gland and that no longer responds to hormone therapy. Genetic testing is now recommended for patients with mCRPC to help doctors understand familial risk and identify patients who may benefit from new treatments. The authors asked doctors questions about their patients, such as their age, symptoms and genetic testing. The authors found that overall genetic testing rates were low, with doctors mostly testing patients they thought were at higher risk of developing cancer. Increased doctor awareness and education are needed to encourage more genetic testing in mCRPC patients. However, doctors claimed that the cost of these tests was a challenge to conducting genetic testing. Aim: To assess homologous recombination repair mutation (HRRm) testing patterns in metastatic castration-resistant prostate cancer. Methods: A point-in-time, international survey conducted January-August 2020. Results: Three-quarters of physicians (oncologists, urologists, specialist surgeons) globally reported access to genetic/genomic testing and just over half were HRRm testers. Surveyed physicians reported HRRm testing and positivity rates for 1913 patients, which were 18.1% and 33.7%, respectively. Of patients tested (n = 347), the most common HRR genes tested were BRCA (91.6%) and ATM (47.3%). Conclusion: Overall testing rates were low, with physicians mostly testing patients they considered higher risk. Increased awareness and education are needed to encourage broader testing, to understand familial risk and to identify patients with worse outcomes or those eligible for life-prolonging treatments.