Do Socio-Economic Determinants Influence DPYD Testing? A Real-World Study of 1478 Cancer Patients Receiving Fluoropyrimidine Chemotherapy

Background: The DPYD gene encodes dihydropyrimidine dehydrogenase (DPD), an enzyme essential for metabolising chemotherapeutic agents such as capecitabine, 5-fluorouracil (5-FU), and tegafur. Variants in this gene can increase the toxicity of these treatments. Methods: This study analysed data from 1478 cancer patients at Nottingham University Hospitals who received chemotherapy between December 2021 and December 2023. The study assessed the prevalence of DPYD variants across different tumour types, ethnic groups, and socioeconomic factors. Results: Overall, DPYD variants were identified in 7% of patients, with higher rates in colorectal cancer (7.9%) and among Caucasian patients (7.4%). The most frequent variant was c.1129-5923C>G (HapB3), found in 75.7% of variant-positive cases. No significant differences in DPYD testing rates were observed across socioeconomic groups or between ethnic backgrounds within our cohort. Conclusions: DPYD variants were prevalent in 7% of the cohort, and testing access was not influenced by socioeconomic status.