5-Fluorouracil-induced toxicity in both male and female reproductive systems: A narrative review

The chemotherapeutic drug 5-flourouracil (5FU) is frequently used to treat a wide range of solid malignant tumors, such as colorectal, pancreatic, gastric, breast, and head and neck cancers. Its antitumoral effects are achieved by interfering with the synthesis of RNA and DNA and by inhibiting thymidylate synthase in both malignant and non-malignant cells. Therefore, it can be responsible for severe toxicities in crucial body organs, including heart, liver, kidney, and reproductive system. Given the fact that 5FU-induced reproductive toxicity may limit the clinical application of this drug, in this study, we aimed to discuss the main locations and mechanisms of the 5FU-induced reproductive toxicity. Initially, we discussed the impact of 5FU on the male reproductive system, which leads to damage of the seminiferous epithelial cells and the development of vacuoles in Sertoli cells. Although no noticeable changes occur at the histopathological level, there is a decrease in the weight of the prostate. Additionally, 5FU causes significant abnormalities in spermatogenesis, including germ cell shedding, spermatid halo formation, polynucleated giant cells, and decreased sperm count. Finally, in females, 5FU-induced reproductive toxicity is characterized by the presence of atretic secondary and antral follicles with reduced numbers of growing follicles, ovarian weight, and maturity impairment.