LINEAR-ACCELERATOR RADIOSURGERY FOR RECURRENT MALIGNANT-TUMORS OF THESKULL BASE

The efficacy of linear accelerator-based radiosurgery for patients who have preirradiated recurrent nasopharyngeal carcinomas and unresectab le recurrent sarcomas invading the base of skull was assessed. Thirtee n patients were treated: 8 patients had carcinomas arising from the na sopharynx (lymphoepithelioma, 4; squamous cell carcinoma, 2; adenoid-c ystic, 2); 5 patients had sarcomas (rhabdomyosarcoma, 1; chordoma, 1; chondrosarcoma, 1; hemangiopericytoma, 2). All patients had had repeat ed tumor resections or irradiation, hindering any further conventional fractionated radiotherapy or surgery. Convergent-beam irradiation was performed with a modified linear accelerator (8-MeV photons). Because of irregular tumor configuration, multiple (up to seven) isocenters h ad to be used in 10 of 13 patients to match the target volume with the reference isodose (60%-80%). Each isocenter was irradiated with 6 to 10 arcs. The median planning target volume was 33 mt (4-128 mt) and th e median dose was 15 Gy (9-24 Gy). Median survival time was 9 months i n 8 patients who had recurrent nasopharyngeal carcinomas, Three patien ts who had complete or partial tumor remission survived 1.5 to 3.5 yea rs. All of the sarcoma patients responded to radiosurgery. After a fol low-up of 28 to 67 months, 4 of 5 patients are alive. This investigati on demonstrates that radiosurgery is an effective tool in palliative t reatment for patients who have recurrent, extensively pretreated nasop haryngeal cancer. Patients who have recurrent sarcomas of the base of skull may be treated for long-term palliation or even for cure.