Radiation-induced bilateral optic neuropathy in cancer of the nasopharynx - Case failure analysis and a review of the literature

Case Report: A case history of unanticipated radiation-induced bilateral op tic neuropathy, 18 months after induction chemotherapy and radiation therap y for a locally advanced nasopharyngeal carcinoma, is presented. Retrospect ive re analysis of the radiation therapy technique, with emphasis on the do ses received by the optic pathway structures, was performed. These re-calcu lations revealed unexpectedly high doses in the range 79 to 82 Gy (cumulati ve external and brachytherapy dose) at the level of the optic nerves, which explained the observed radiation injury. Conclusion: Routine implementation of computed tomography for 3D dose plann ing purposes is therefore advocated. Review of the current literature confi rms the importance of 3D dose planning in avoiding this complication and hi ghlights the role of MRI in establishing the diagnosis of radiation-induced optic neuropathy.