Incidence and outcomes of radiation-induced late cranial neuropathy in 10-year survivors of head and neck cancer

Objectives: To characterize the late cranial neuropathy among 10-year survivors of head and neck cancer treatment. Materials and methods: We retrospectively evaluated patients treated with curative-intent radiation for HNC between 1990 and 2005 at a single institution with systematic multidisciplinary follow-up >= 10 years. New findings of CNP were considered radiation-induced when examination, imaging and/or biopsy did not demonstrate a structural or malignant cause. Cox proportional hazards modeling was used for univariable analysis (UVA) and multivariable analysis (MVA) for time to CNP after completion of radiation. Results: We identified 112 patients with no evidence of disease and follow-up >= 10 years (median 12.2). Sixteen (14%) patients developed at least one CNP. The median time to CNP was 7.7 years (range 0.6-10.6 years). Most common was CN XII deficit in eight patients (7%), followed by CN X deficit in seven patients (6%). Others included CN V deficit in three, and CN XI deficit in two. Eight of the thirteen patients with a CN X and/or CN XII deficit required a permanent gastrostomy tube. On UVA, site of primary disease, post-radiation neck dissection, chemotherapy, and radiation dose were significantly associated with increased risk of CNP. Conclusion: Iatrogenic CNP may develop years after head and neck cancer treatment and often leads to swallowing dysfunction. Long-term follow up is essential for these patients receiving head and neck radiation.