Association of leukopenia in the development of cancer chemotherapy‐induced oral mucositis and its severity

To prevent oral mucositis, it is important to understand its associated risk factors, such as highly cytotoxic chemotherapeutic agents, sex, and low body weight. However, to the best of our knowledge, no study has investigated the association between chemotherapy‐induced myelosuppression and oral mucositis in Japan. In this study, we examined the relationship between chemotherapy‐induced leukopenia and the severity of oral mucositis.We conducted a retrospective cohort study of patients who received oral care interventions during cancer chemotherapy. Hematological values were obtained at the initiation of chemotherapy and on the proximal day of changes in the grade (Gr) of oral mucositis. The Gr of oral mucositis was assessed by dentists and dental hygienists using the Common Terminology Criteria for Adverse Events (version 5.0).The data of 79 patients were analyzed during the study period. The incidence of oral mucositis was 7/79 (8.9%). The incidences of grades 1–4 were 4/79 (5.1%), 2/79 (2.5%), 0/79 (0%), and 1/79 (1.3%), respectively. Notably, the incidence of oral mucositis was significantly higher in patients with lower white blood cell and neutrophil counts (p < 0.01). Logistic regression analysis further revealed that patients with Gr 2 or higher leukopenia had a significantly higher risk of developing Grade 2 or higher oral mucositis (adjusted odds ratio: 5.2; 95% confidence interval: 1.60–17.0; p = 0.0062).Cancer chemotherapy induced‐oral mucositis may be at great risk in patients with Gr 2 or higher leukopenia.