Aim: To assess the patterns of genetic testing for homologous recombination repair mutations in patients with metastatic castration-resistant prostate cancer (mCRPC) pre-PARP inhibitors approval. Patients & methods: mCRPC patients were selected in an oncology electronic medical records database. Patterns and predictors of testing for ATM, BRCA1/2, CDK12, PALB2 and FANCA gene alterations were assessed. Results: Of 5213 mCRPC patients, 674 (13%) had a documented genetic test. The number of tested patients increased from 1 in 2013 to 313 in 2018 (out of 3161 and 3010 clinically active patients, respectively). Receiving care in an academic oncology center (versus a community-based center) strongly predicted genetic testing (hazard ratio = 2.41). Conclusion: The use of and access to genetic testing pre-PARP inhibitor approval was suboptimal.
Keywords: HRR gene alterations; PARP inhibitors; genetic testing; metastatic castration-resistant prostate cancer; predictors; real world.
Lay abstract In 2017, US guidelines recommended the use of genetic testing in patients with metastatic castration-resistant prostate cancer (mCRPC). While the initial goal of genetic testing was to guide referral to genetic counselling and clinical trial enrollment, it is now also used to identify patients who could benefit from new drugs that target specific molecular defects. Using medical record data of US patients with mCRPC, we found that the rates of genetic testing and the breadth of molecular defects tested were suboptimal from 2013 to 2019. We also found lower rates of genetic testing in patients treated in community-based centers compared with those treated in academic oncology centers. These results underscore the importance of increasing the take up rate of genetic testing in patients with mCRPC to help guide treatment decisions.