Long-term treatment outcome of recurrent nasopharyngeal carcinoma treated with salvage intensity modulated radiotherapy.

PURPOSE: To evaluate the long-term treatment outcome in patients with recurrent nasopharyngeal carcinoma (NPC) treated with salvage intensity modulated radiotherapy (IMRT).

MATERIALS AND METHODS: One hundred and fifty one previously irradiation NPC patients with recurrent disease and re-irradiated by IMRT between 2001 and 2006 had been reviewed. The disease was re-stage I in 7, re-stage II in 21, re-stage III in 50 and re-stage IV in 73. Thirty-seven patients received concurrent chemotherapy, 39 had induction chemotherapy and 75 had radiotherapy alone.

RESULTS: All patients completed the planned IMRT. The median volume of the recurrent gross target volume of nasopharynx (rGTVnx) was 42.2 cm(3) (range 1.5-146.3 cm(3)). The median mean re-irradiation dose to the rGTVnx was 70.4Gy (range 62.1-77.6Gy). The median follow-up time after re-irradiation was 40.0 months (range 1.9-116.9 month). The 5-year local control rate (LCR) and overall survival rate (OS) for re-stage I, II, III, IV were 80.0%, 85.0%, 80.0%, 78.7% and 71.4%, 62.9%, 35.5%, 30.2%, respectively. Multivariate analysis indicated that rT classification (hazard ratio (HR), 2.02; 95%confidence interval (CI), 1.03-3.97; P=0.04) and the volume of rGTVnx (HR, 2.05; 95%CI, 1.31-3.22; P<0.01) were independent predictors for OS. Patients (39.0%) with re-stage III or IV disease experienced Grade 3 or 4 late toxicities.

CONCLUSION: Re-irradiation by IMRT for recurrent NPC resulted in encouraging local control. The clinical outcome for patients with early re-stage diseases was satisfactory. Further investigations, focus on optimising radiation dose and establishing effective treatment strategies, are warranted for advanced recurrent disease in order to improve overall survival and minimise late toxicity.