A simple blood test, compulsory since 2019, nevertheless makes it possible to prevent severe toxicities linked to certain chemotherapy treatments. The National Medicines Safety Agency (ANSM) recalls its vital nature.
Fluoropyrimidine-based chemotherapy: serious but avoidable side effects
Fluoropyrimidines are among the most prescribed anticancer treatments. Their effectiveness no longer needs to be demonstrated. But their metabolism depends on an enzyme,
dihydropyrimidine dehydrogenase (DPD)responsible for eliminating these molecules from the body.
When this enzyme is absent or deficient, the drug accumulates and causes serious toxicities: mucositis, neutropenia, severe diarrhea, even death.
According to the National Cancer Institute (INCa) and the High Authority for Health (HAS), 1 in 5 patients suffers from severe side effects and up to 1 in 1,000 patients can die.
Since 2018, the ANSM has conducted annual surveys with the regional pharmacovigilance centers (CRPV) to identify so-called “avoidable” serious cases, that is to say occurring despite the clear recommendation of prior screening.
The last survey in 2024 identified a dramatic case linked to the absence of a test before treatment, reminding us that constant vigilance is essential.
However, screening has been compulsory since April 2019via a blood uracilemia measurementwhich makes it possible to determine whether the patient has a complete or partial DPD deficiency — a sine qua non condition for adjusting the dose or contraindicating the treatment.
Screening for DPD deficiency: a safety reflex that hospitals have integrated
Good news: according to the national survey carried out at the end of 2024 by ResOMEDIT, at the request of the Directorate General of Health (DGS), French hospitals mainly respect this obligation.
On 590 establishments interviewed, 86% of patients benefited from a uracilemia assay, and in 82% of casesthe result was returned before the first treatment. No patient with total DPD deficiency received 5-FU.
Encouraging figures, welcomed by the DGS, even if room for improvement remains: 40% of establishments do not yet have a dosage adaptation protocol, and 37% do not have automatic software alerts.
This shared vigilance illustrates the concrete consideration of alerts issued by patients themselves. “This national survey confirms that healthcare professionals have largely integrated screening for DPD deficiency into their practices, thus contributing to making 5-FU treatments safer. It also illustrates the capacity of health authorities to respond concretely to patients’ challenges, by mobilizing all stakeholders to further improve the quality and safety of care.”.
Capecitabine, an urban treatment under close surveillance
Although hospitals have made progress, vigilance remains required in community medicine. There capecitabineoral chemotherapy often prescribed at home, has been at the heart of a serious preventable case in 2024: the drug had been prescribed and administered before receiving the screening result.
This failure reminds us that the test is not a simple formality but a vital step.
The DGS announces that it wants to verify the conditions of use of capecitabine in the city, “to ensure that treated patients also benefit from a uracilemic dosage. This work will notably involve the Health Insurance Fund (CNAM).”she specifies in the press release.
The issue is all the more crucial as these treatments, administered on an outpatient basis, often escape hospital control protocols. Of the reminder pop-up have been integrated into prescription software certified by the High Authority of Health, to avoid any delivery without uracilemia results.
Finally, increased caution in patients withkidney failurewhere the interpretation of the test can be distorted: a wrong reading of the results could unnecessarily deprive a patient of effective treatment.
This mobilization around the DPD deficiency tells of a silent but essential advance: that of a safer, more attentive, more humane medicine. Behind each uracilemia measurement, it is a life that we are protecting.
FAQ – Screening for DPD deficiency before chemotherapy
1. Why is the DPD deficiency screening test mandatory before chemotherapy?
This blood test detects a possible abnormality of the DPD enzyme, essential for eliminating certain cancer drugs. Without this screening, the treatment can become toxic and cause serious or even fatal effects. Since 2019, its result is essential before any prescription of 5-FU or capecitabine.
2. Is the test also necessary for chemotherapy taken at home?
Yes, particularly for capecitabine, prescribed in community medicine. This drug acts like 5-FU and presents the same risks of toxicity in the event of DPD deficiency. The test result must always be known before the first taking, even outside the hospital.