Long-term changes of irradiated oral mucosa in patients with head and neck carcinoma

Head and neck cancer treatments, such as radiation therapy (RT), often cause acute tissue changes, but still little is known about the long-term effects. This study aimed to identify pathological changes and the role of transmembrane MUC1 (tMUC1) in the oral mucosa and its correlation to RT. A total of 87 patients were recruited for the study: 34 irradiated patients and 53 healthy controls (HC). The data of irradiation dose, hyperbaric oxygen therapy (HBOT), and radiation-to-biopsy interval (RTBI) were collected. Samples of the patient's oral mucosa were prepared for histological, immunohistological, electron microscopical, and immunoelectron microscopical studies. Staining intensity of tMUC1 was significantly stronger in the irradiated patients than in the controls. Only patients with RTBI of 17 months or less presented cell hyperchromatism and low intensity of tMUC1 staining. Long-term changes were not affected by the local dose. HBOT redirected tMUC1 staining toward values of the control group. The irradiated oral mucosa appears to improve over time, and HBOT could also be a contributing factor in long-term positive changes. tMUC1 can be used as a biomarker when examining the oral mucosal health after cancer treatment.