Worldwide genetic testing rates are low for patients with prostate cancer

An international survey showed alarmingly low rates of genetic testing in patients with metastatic castration-resistant prostate cancer (mCRPC), according to results published in the journal Future Oncology.¹

The researchers specifically assessed rates of testing for homologous recombination repair mutations (HRRm). The findings showed that despite about 75% of the surveyed clinicians (urologists, oncologists, specialist surgeons) having access to genetic/genomic testing, only 18.1% of patients with mCRPC received HRRm testing.

“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,” the authors wrote.

Genomic testing in mCRPC has become critical with the emergence of PARP inhibitors, such as olaparib (Lynparza) and rucaparib (Rubraca), for the treatment of patients with HRRm-associated mCRPC.

The study involved a real-world, point-in-time survey of oncologists, urologists, specialist surgeons, and their patients in the United States, Europe (EU5), and Japan. The surveys were completed between January 2020 and August 2020.

Overall, 391 physicians completed surveys comprised of questions about their genomic testing access/practice for patients with mCRPC. The researchers also collected 1913 patient forms.

Of the 391 physicians, 73.7% (n = 288) reported that they had access to genetic/genomic testing; however, only 347 (18.1%) of the 1913 patients reported that they received HRRm testing.

The rates of HRRm testing were highest in the United States and Germany at 38% and 34%, respectively. The rates were much lower in the EU5, UK, and Japan, at 16%, 6%, and 3%, respectively.

For all countries except Japan BRCA1 (≥82% of patients) and BRCA2 (≥79%) were the most frequently tested genes. The most commonly tested gene in Japan was ATM.

Across all patients, the HRRm positivity rate was 34%, which according to the researchers indicated that, “physicians were mostly testing mCRPC patients whom they considered higher risk, despite guideline recommendations for genetic testing for HRRm in all patients with metastatic prostate cancer.”

Across all regions, the challenge to conducting genetic testing that was most commonly reported was cost. This was the case for 167 (42.7%) of the 391 physician respondents. Another common barrier reported across all regions/countries was “limited physician awareness of genomic/genetic testing for prostate cancer.” This was particularly an issue in Japan (42.2%) and the United Kingdom (40.5%).

Specifically for US physician respondents, the most common barriers to testing reported were cost (50%), not reimbursed (26%), sending out for tests (25%), inadequate sample available (25%), and patients refusal (25%).

In their conclusion, the authors wrote, “Although advances in this area are still relatively recent and developing (especially in terms of approved treatment options and implementation of guideline recommendations for treatment and genetic/genomic testing), it is important to raise awareness of and access to HRRm testing for patients with mCRPC. It is also important to consider potential challenges, including practical considerations for integrating genetic/genomic testing into clinical practice, and to explore solutions for overcoming those potential barriers.”

Reference

1. Leith A, Ribbands A, Kim J, et al. Real-world homologous recombination repair mutation testing in metastatic castration-resistant prostate cancer in the USA, Europe and Japan [published online January 19, 2022]. Future Oncol. doi: 10.2217/fon-2021-1113