Abstract 3892: Upfront DPD screening with adaptive dosing to secure 5-FU administration in head and neck cancer patients

Upfront screening for dihydropyrimidine dehydrogenase (DPD) deficiency in patients scheduled for 5-FU-based protocols should reduce the risk of treatment-related toxicities by preventive adaptive dosing. Our group has developed a simple, rapid and cheap functional testing that helps categorizing patients on their DPD status and detecting poor metabolizer (PM) patients, using UH2/U ratio measurement in plasma as a surrogate for DPD activity. 5-FU dosing can be next tailored using a geometric scale, according to the level of DPD deficiency. We report here the performances of this adaptive dosing strategy implemented in routine clinical practice in head and neck cancer patients. A total of 218 evaluable adult patients were scheduled for a 5-FU-regimen (mostly TPF protocol), with prospective search for DPD deficiency and, if required, tailored dosing. Overall, 20 patients (9%) were identified as PM and received subsequently an average 20-50% reduced dose of 5-FU as compared with extensive metabolizer (EM) patients (2102 ± 254 mg VS. 2577 ±353mg, p Citation Format: Joseph Ciccolini, Manon Launay, Charlotte Dupuis, Florence Duffaud, Bruno Lacarelle, Sébastien Salas. Upfront DPD screening with adaptive dosing to secure 5-FU administration in head and neck cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3892.