Toxicities associated with chemotherapy regimens containing a fluoropyrimidine: A real-life evaluation in France

Despite fluoropyrimidines (FPs) constituting the main component of the chemotherapy combination protocols in 50% of chemotherapies for solid tumour treatments, incidence data for FP-related toxicity are poorly documented in real life. This study evaluated the number of patients receiving FP-based chemotherapies in France, along with the true incidence of FP-related serious adverse effects (SAEs) before the recent mandatory dihydropyrimidine dehydrogenase (DPD)-screening was introduced by French health authorities, DPD being the rate-limiting enzyme of 5-fluorouracil (5-FU) catabolism. Exhaustive data on the number of patients treated with FP-based chemotherapy in 2013–2014 were collected in the Centre-Val de Loire region of France. True incidence of SAEs was extracted from a cohort of 513 patients with incident solid tumours receiving first-line FP-based chemotherapy. After extrapolation at national level, we estimated that 76,200 patients are currently treated annually with 5FU (53,100 patients, 62% digestive system-related versus 26% breast cancers versus 12% head and neck cancers) or capecitabine (23,100 patients, 45% digestive system-related versus 37% breast cancers versus 18% non-documented). Earlier (in the first two cycles) the SAE incidence rate was 19.3% (95% confidence interval (CI) 16–23%) including one toxic death (0.2%, 95%CI 0–1%). SAE incidence rate was 32.2% (95%CI 28–36%) over the first 6 months of treatment. Incidence of death, life-threatening prognosis or incapacity/disability was 1.4% (95%CI 0.4–2.4%) and 1.6% (95%CI 0.5–2.6%) during first two cycles and first 6 months, respectively. These data highlight the significant public health issue related to FP toxicity, with around 1200 patients developing FP-related life-threatening prognosis or incapacity/disability annually in France, including 150 toxic deaths. It is hoped that DPD-deficiency screening will reduce such iatrogenic events and eradicate toxic deaths. •Early incidence rate of serious adverse events with fluoropyrimidines is 19.3%.•The number of FP-related toxic deaths is estimated around 150/year in France.•Death, life-threatening prognosis or incapacity affect 1200 patients/year in France.•These are declared to a pharmacovigilance centre in only 12.5% of cases.•Systematic pre-therapeutic screening of DPD deficiency is urgently needed.