Application of stereotactic radiosurgery to the head and neck region.

Nasopharyngeal carcinoma recurrent following primary radiation therapy has been treated with surgery and reirradiation. Reirradiation is often limited by the tolerance of structures previously treated. Radiosurgery was used to boost the recurrent site while avoiding critical structures. Seven patients were evaluated for treatment. Three patients met requirements for treatment. The lesions invaded the parapharyngeal region, the base of skull, cavernous sinus, cranial nerves, or carotid artery. Treatment included a radiosurgery boost utilizing multiple isocenters, noncoplanar arcs, and arc weighting, to yield a plan conforming to the tumors while avoiding critical anatomical structures. The patients tolerated the procedure well with minor acute side effects. Follow-up included magnetic resonance imaging (MRI) and positron emission tomography (PET). Two lesions responded, and one had no significant change. One patient had a regional recurrence. Two patients had distance recurrence. Long term side effects include trismus, parotiditis, ear fullness, hemorrhage, and pain. Radiosurgery may improve the local control rate of such lesions, however, with the severe long term complications of single fraction radiosurgery in the head and neck region this procedure may be more beneficial if the treatment is fractionated.