Stereotactic radiosurgery plus intracavitary irradiation in the salvage of nasopharyngeal carcinoma

Abstract

We sought to assess the efficacy and complications of linear accelerator-based stereotactic radiosurgery (SRS) plus intracavitary irradiation (ICI) as salvage treatment for local persistent and recurrent nasopharyngeal carcinoma (NPC) after primary external beam radiotherapy (EBRT). Between July 1995 and June 2003, 36 patients (25 men and 11 women; median age, 48 years; range, 22-66 years) with local recurrent NPC confined to the nasopharynx (rT1) or limited extension to the parapharynx and nasal cavity (rT2) were treated with SRS plus ICI. Nineteen patients had rT1 and 17 had rT2 disease. Five patients (13.8%) had persistent disease, and 31 patients (86.1%) had recurrent disease using the definition of >4 months after the primary treatment as recurrent relapse. The median target volume was 36.3 cm(3) (range, 10.3-56.2 cm(3)) for the SRS treatment. All patients received 18 Gy to the 90% isodose line followed by two separate ICI 6 Gy each to 0.5 cm from the surface of the endotracheal balloon. Patients were assessed with serial nasoendoscopy and repeat scans (CT or MRI) at 3 months, and suspicious lesions were rebiopsied. The median follow-up for surviving patients was 4.24 years (range, 0.73-8.81 years). Twenty-two of 36 (61%) patients were alive at the time of reporting. Twenty patients were free of disease, and two patients were alive with disease. Fourteen of 36 (39%) patients had died (five of distant metastases, six of local recurrences, two of both local disease and distant metastases, and one of unrelated cause). Patients with rT1 disease (median survival not reached) fared better that patients with rT2 disease (median survival, 4.6 years). The actuarial 5-year disease-free survival and overall survival (OS) were 57% (rT1 78%, rT2 39%) and 62% (rT1 80%, rT2 48%), respectively. The actuarial 5-year local control was 65% (rT1 82%, rT2 49%). The treatment was well tolerated with no significant acute complications. Sixteen patients (44%) had late complications, including palatal fibrosis in six patients (17%), trismus in seven patients (20%), cranial nerve palsies in seven patients (20%), temporal lobe necrosis in two patients (8%), and osteoradionecrosis of the skull base in six patients (17%). The complication-free survival rates at 2 and 5 years were 70% (95% confidence interval [CI], 56% to 87%) and 31% (95% CI, 17% to 56%), respectively. No patient died as a direct result of the late complication. Although our series is small, the combination of SRS and ICI seems to be an effective salvage treatment for early-stage recurrent NPC. The OS of 62% at 5 years is very encouraging and favorable compared with reported reirradiation or surgical series. The late complications are considerable but expected because of the high doses of radiation previously delivered. The ideal dose fractionation for SRS and ICI is unknown and remains to be defined.