Background. Lhermitte's sign (LS) is a side effect of radiotherapy (RT) on the spinal cord and typically occurs shortly after the procedure has been conducted. When treating patients with cancer of the head and neck region with irradiation, it remains difficult to avoid exposing the cervical spinal cord to unintended radiation. In this study, we focused on nasopharyngeal cancer (NPC) alone and looked for various parameters that might influence the occurrence of LS associated with this disease after RT.
Methods. From 1979 through 1990, 1171 patients with NPC completed RT either with or without chemotherapy at the Lin-Kou Medical Center, Chang Gung Memorial Hospital (CGMH), Tao-Yuan, Taiwan; the RT regimens for these treated patients were very similar. The nasopharyngeal tumor was treated to 75 Gy by photon teletherapy and after-loading brachytherapy. The neck lymphatics were irradiated with photon irradiation to 46.8 Gy and then boosted with electron beams to 10 to 30 Gy, in accordance with the patient's nodal status, either unilaterally or bilaterally. Every patient was followed monthly for the first 3 months after therapy and subsequently every 2 to 3 months for the next 2 years and, finally, every 6 months thereafter. At follow-up, a neurologic checkup of each patient was performed to determine whether any injury to the spinal cord or brain stem had arisen.
Results. LS was observed for 121 patients (10.3%). The median development time for such signs was 3.0 months after the completion of RT (range, 0.2 -72 months),