Purpose: To assess the outcome of and determine prognostic factors for locally recurrent nasopharyngeal carcinoma (NPC) in patients treated with a second course of radiotherapy (RT).
Materials and methods: From 1982 to 1995, 186 NPC patients, who had initially been treated in the Department of Radiation Oncology, Chang Gung Memorial Hospital-Linkou, developed local recurrence in the nasopharynx and were re-treated with RT (>/=20 Gy). The time from the initial RT to re-treatment ranged from 8 to 136 months (median: 23 months). All patients were treated with external RT and conformal radiotherapy was used in 35 patients after 1993. Fifteen received radiosurgery as a boost treatment. The RT dose at the nasopharyngeal tumor area ranged from 20 to 67.2 Gy (median 50 Gy). Eighty-two patients received one to eight courses of cisplatin-based chemotherapy in addition to RT.
Results: The 1-, 3- and 5-year survival was 54.9, 22. 1 and 12.4%, respectively. Patients whose tumor relapsed later than 2 years after the first treatment had a better survival than those with earlier relapse (3-year survival: 30.1 vs. 10.8%; P=0.015), but the difference became insignificant in patients who received >/=50 Gy. Patients without evidence of intracranial invasion or cranial nerve palsy had better survival than those with such lesions (3-year survival: 30.9 vs. 3.7%; P=0.006). A re-treatment dose >/=50 Gy yielded better survival (3-year survival: 22.8 vs. 18.5%; P=0.003). Addition use of radiosurgery may improve survival. The use of chemotherapy did not improve survival. Conformal radiotherapy resulted in significantly fewer severe complications than conventional RT.
Conclusions: A repeat course of RT for locally recurrent NPC successfully prolongs survival in a significant number of patients. Intracranial invasion and/or cranial nerve palsy and re-treatment dose affect the prognosis, with a dose of >/=50 Gy significantly improving survival. Radiosurgery boost may also improve survival. Our preliminary data indicates that conformal radiotherapy may decrease the severity of radiation-induced complications. However; longer follow-up and larger sample size is necessary to document the findings.