Survey-based perspectives and reported barriers to DPYD testing among U.S. oncologists

Patients with cancer with deleterious DPYD variants are at significantly increased risk for severe toxicity with standard fluoropyrimidine doses. Prior to recent guidelines recommending it, the uptake of pre-treatment DPYD testing in the United States has been low. We aimed to explore oncologists' perceptions and barriers to DPYD testing adoption on a national level.

Survey invitations were sent to U.S. oncologists listed in the American Medical Association (AMA) Masterfile in April and May 2025. The surveys assessed physician knowledge, attitudes, and perceptions of DPYD testing in clinics caring for patients with cancer in the United States. Descriptive statistics were used to evaluate survey responses.

Of 5,525 physicians invited to participate, 47 oncologists completed the survey (response rate: 0.85%). The majority (85%) indicated that DPYD testing could help them manage patients; however, only 34% reported routinely performing DPYD testing. Most physicians (77%) agreed that adequate resources were available to order DPYD testing. When directly asked, 36% indicated that limited laboratory access was a barrier. In open-ended responses, respondents identified insurance reimbursement concerns (21%) and prolonged turnaround time (19%) as additional barriers. Forty-three percent reported needing assistance interpreting results and applying them to drug selection and dosing. Webinars (25.5%) and self-paced online modules (21%) were the most preferred educational modalities.

Most respondents indicated that DPYD testing could help manage patients, yet concerns persist. While regulatory guidance is evolving, these preliminary findings from a small sample highlight the need for future research to characterize implementation barriers and inform policy development.

Our findings highlight gaps in implementation that can inform targeted strategies to improve the integration of DPYD testing into oncology practice, with the potential to enhance patient safety and reduce fluoropyrimidine-related toxicity.