Sex differences in fluorouracil-induced stomatitis

Purpose: A meta-analysis of six North Central Cancer Treatment Group (NCCTG) trials involving patients receiving their first ever fluorouracil (5- FU)-based chemotherapy was undertaken to explore the association of sex with reports of the incidence and severity of stomatitis. Patients and Methods: Data were obtained on a total of 731 patients (402 men and 329 women). Comparisons of incidence and severity rates and average stomatitis across sex were performed using standard binomial testing and t tests, respectively. Logistic regression analysis and a weighted analysis using data summarized to study level served as evidence of cross-validation. Results: Women reported stomatitis both more often and with greater severity than did men. The incidence of any stomatitis for women was 63% versus 52% for men (P = .002). The incidence of severe or very severe stomatitis for men and women was 22% and 12%, respectively (P = .0006). On average, women reported stomatitis of roughly 0.4 points higher than men on a 0 to 4 ordinal scale (P < .00001). Comparison of results across treatment and placebo arms was carried out to validate the initial findings. Logistic regression modelling further confirmed the results conditional on the presence of a number of potentially confounding covariates. Women were also 11% more likely than men to experience leukopenia of common toxicity criteria grade ≥ 1, (70% v 59%, respectively; P < .00001) and grade 3+ (18% v 11%, respectively; P = .004). Conclusion: More women than men reported 5-FU-induced stomatitis. The precise mechanism resulting in different degrees of stomatitis across sex is not evident.