The association between cumulative radiation dose and the incidence of severe oral mucositis in head and neck cancers during radiotherapy.

BACKGROUND Quality of life can be influenced by oral mucositis (OM), and it is necessary to implement OM management strategies before the initiation of radiotherapy (RT) in patients with head and neck cancer (HNC). AIMS To examine the association between the cumulative radiation dose and the incidence of severe OM in HNC patients receiving RT. METHODS AND RESULTS A retrospective observational cohort study was conducted in a Showa University Fujigaoka Hospital, in Japan. We retrospectively analyzed 94 patients with HNC who developed OM during RT. We defined OM as a more than grade 2 OM. The cumulative incidence of OM curves of the two categories was estimated using the Kaplan-Meier method and compared using the log-rank test. We estimated the hazard ratio (HR) for OM after the adjustment of factors for covariates using Cox's regression analysis. Patients with smoking history had a significantly later development of OM than those with no smoking history (20 Gy-incidence OM 68.7% vs 39.7%, P = .003). In contrast, patients undergoing concurrent chemotherapy had an earlier development of OM than those undergoing RT alone (20 Gy-incidence OM 24.2% vs 55.7%, P < .001). Multivariate analysis revealed that no smoking history and concurrent chemotherapy were independent predictive factors, with a HR of 0.526 (P = .025) and 2.690 (P < .001), respectively. CONCLUSION We demonstrated that no smoking history and concurrent chemotherapy may be predictive of OM in HNC patients.