Increased Risk Of Cranial Nerve Palsy In 10-Year Survivors Of Head And Neck Cancer After Primary Surgery And Adjuvant Radiation

To characterize the late complication of cranial nerve palsy (CNP) among 10-year survivors after radiation therapy for head and neck cancer (HNC). We retrospectively evaluated patients treated with curative-intent radiation for HNC between 1990-2005 at a single institution with systematic multidisciplinary follow-up ≥10 years. CNP was diagnosed by exclusion. Patients with new CNP appreciated on clinic examination were evaluated with imaging and biopsy as necessary. When evaluation did not identify a structural or malignant cause to the new CNP, it was attributed to a late complication of treatment. Cox model was used for multivariable analysis (MVA) for time to CNP after completion of radiation. Parameters included in MVA were subsite of primary disease (pharynx/larynx vs others), T-stage (T3-T4 vs T1-T2), N-stage (N2-N3 vs N0-N1), primary surgery before radiation (yes vs no), postradiation neck dissection (yes vs no), chemotherapy (yes vs no), radiation dose (continuous variable). We identified 112 patients with follow-up ≥ 10 years (median 12.2 years). The primary tumor sites were pharynx (42%), oral cavity (34%), larynx (13%), and other (11%). Forty-four percent underwent surgery before radiation, 24% had post-radiation neck dissection, and 47% received chemotherapy. Nearly all patients (96%) were treated with 2D radiation planning with prescription to isocenter, with a median prescribed radiation dose of 70 Gy (50-75 Gy). A total of 16 (14%) patients were found to have late complication of at least one CNP, including 6 with 2 separate CNPs, and 1 with 3 separate CNPs. The median time to first documented CNP among these 16 patients was 7.7 years (range 0.6-10.6 years). The most common CNP was XII deficit in 8 patients (7%), appreciated as a flaccid, atrophied hemi-tongue with ipsilateral deviation on protrusion. Next was cranial nerve X deficit in 7 patients (6%), appreciated as a vocal cord paralysis on laryngeal examination. Others included cranial nerve V deficit in 3 patients, appreciated as facial numbness over the distribution of trigeminal nerve, and cranial nerve XI deficit in 2 patients, appreciated as weakness or atrophy of trapezius muscle. On MVA, treatment with primary surgery was the only significant factor associated with the development of CNP after completion of radiation, with hazard ratio (HR) of 7.1 (95% CI 1.4-37.3), P=.02. Chemotherapy approached significance in MVA for increased risk of CNP, with HR of 4.0 (95% CI 0.8-18.0), P=.07. Iatrogenic CNP can develop years after completion of head and neck cancer treatment. Patients who underwent surgery prior to radiation seemed to have significantly increased risk of late CNP.