Determination of plasma uracil as a screening for dihydropyrimidine dehydrogenase deficiency: clinical application in oncological treatments.

AIMS: Treatment with dihydropyrimidines poses a significant risk of serious adverse reactions for patients with dihydropyrimidine dehydrogenase (DPD) deficiency. This study seeks to analyse the correlation between DPD deficiency and plasmatic uracil values in patients who are candidates for a fluoropyrimidine scheme. It also studies the incidence of adverse events (AEs) in patients with DPD deficiency established with plasmatic uracil determination. METHODS: This was a retrospective observational study conducted in a tertiary level establishment from September 2020 to April 2021. Patients included were diagnosed with gastrointestinal tumours, were of good status, and were initiated into a fluoropyrimidine-based regimen. The incidence and grade of AEs, according Common Terminology Criteria for Adverse Events (CTCAE), were collected and compared in patients with and without DPD deficiency. RESULTS: 119 patients diagnosed with gastrointestinal cancer met the inclusion criteria. In 92 (77%) patients there was no DPD deficiency according to plasmatic uracil thresholds. In the group of patients without deficit, dose reductions oscillated between 10-25% (mean 17.4%). In the no DPD deficiency group, 43 (46%) patients experienced AEs. Patients who had a DPD deficiency according to plasmatic uracil measurements were started on a 5-fluorouracil (5-FU) regimen with a dose reduction of 15-50% (mean 35%). In this group, 12 patients (44%) experienced some AEs. CONCLUSION: New research is needed to clarify the correlation between plasma uracil values and DPD deficiency to achieve an optimal balance between clinical benefit and toxicity.

Molecular epidemiology of Anisakis spp. in blue whiting Micromesistius poutassou in eastern waters of Spain, western Mediterranean Sea.

The infection of blue whiting Micromesistius poutassou from the western Mediterranean Sea, off the eastern coast of Spain, with larvae of Anisakis spp. was studied. Between April 2016 and April 2017, 140 fish were analyzed. Total epidemiological data showed that the prevalence of Anisakis spp. was 29.3% and the mean intensity 1.8. Of the 74 larvae collected, 61% were type I and the remaining 39%, type II. Of the former, 91% were molecularly identified as Anisakis pegreffii (P = 19.3%; MI = 1.4), 2.2% as Anisakis simplex s.s. (P = 0.7%; MI = 1.0), while the rest (6.7%) showed a recombinant genotype between the two (P = 2.1%; MI = 1.0). All the type II larvae analyzed were molecularly identified as Anisakis physeteris (P = 10.0%; MI = 2.1). Three fish (2.1%) were found to have larvae in the muscle, while two were found with 1 larva of A. pegreffii and one with two larvae (1 A. simplex s.s. and 1 A. pegreffii). Statistical analysis showed that the prevalence of Anisakis spp. in blue whiting was higher in spring than in autumn (P < 0.001), probably due to the greater size (and age) of the fish and related to factors as diet shift, accumulation with age and higher food intake. Analysis of the data suggested that blue whiting were first infected with Anisakis type I (mean age 2.3 years) and later with Anisakis type II (mean age 2.7 years), probably due to the diet changing with age, with the incorporation of the paratenic/intermediate host species of these parasites. In any case, the public health authorities must continue to emphasize the need for suitable thermal treatment (freezing or cooking) of the fish prior to consumption.