Microvascular changes in radiation-induced oral mucositis.

ABSTRACT

BACKGROUND: Mucositis is one of the most debilitating side effects of head and neck cancer therapy and is currently believed to arise from an inflammatory cascade leading to cellular damage. However, no effective treatment has been identified despite extensive attempts with anti-inflammatory medications. OBJECTIVE: To compare real-time microvascular inflammatory changes with oral mucositis levels in patients undergoing radiotherapy or chemoradiotherapy for head and neck tumours. DESIGN: Prospective, longitudinal, cohort, observational study. SETTING: Regional cancer program. METHODS: Twenty patients with head and neck tumours were assessed on a weekly basis throughout the course of radiotherapy. Levels of mucositis were graded objectively using the Oral Mucositis Assessment Scale and subjectively using a patient symptom questionnaire. Video imaging of the sublingual microcirculation was obtained using orthogonal polarized spectral imaging to quantify inflammatory markers such as microcirculatory velocity, white blood cell margination, and extravasation. RESULTS: Despite very high levels of objective and subjective mucositis, inflammatory changes were not present in the microcirculation. CONCLUSIONS: Typical microvascular inflammatory changes are not demonstrated in radiation-induced mucositis. These findings contradict the currently proposed mechanism of mucosal damage and may therefore have important implications in the development of novel therapeutic interventions.