Lhermitte sign and myelopathy after irradiation of the cervical spinal cord in radiotherapy treatment of head and neck cancer

The goal of this work was to examine toxicity and risk factors after irradiation of the cervical spinal cord. A total of 437 patients irradiated for a laryngeal and oropharyngeal carcinoma were eligible (median follow-up 27 months). Spinal cord contouring was defined differently over time as anatomically defined spinal cord area (SCA) and the spinal cord on CT (SC) with a margin of 3 or 5 mm (SCP3/SCP5). None developed chronic progressive radiation myelopathy (CPRM) (maximum spinal dose 21.8-69 Gy); 3.9% (17/437) developed a Lhermitte sign (LS) with a median duration of 6 months (range 1-30 months) and was reversible in all patients. Risk factors for developing LS were younger age (52 vs. 61 years, p <0.001), accelerated RT (12/17 patients, p <0.005), and dose-volume relationships for SCA with a parts per thousand yenaEuro parts per thousand 45 Gy of 14.15 cm(3) and 7.9 cm(3) for patients with and without LS, respectively. LS is more frequently observed in younger patients and in patients treated with accelerated radiotherapy. A dose-volume relationship was seen for V45 in the case of SCA. For higher doses, no clear dose-volume relationships were observed.