Effectiveness and Toxicities of Intensity-Modulated Radiotherapy for Patients with Locally Recurrent Nasopharyngeal Carcinoma

Purpose: To analyze the effectiveness and toxicities in the re-irradiation of locally recurrent nasopharyngeal carcinoma (NPC) using intensity-modulated radiotherapy (IMRT). Methods: This is a retrospective analysis of 54 NPC patients with local recurrence re-irradiated with IMRT. The re-staging for rT1, rT2, rT3, rT4 were 3 (5.6%), 8 (14.8%), 9 (16.7%), 34 (63%) respectively. The average dose to GTV was 69.95 Gy (49.8-76.58 Gy), the average BED3Gy was 116.8 Gy (83.5-127.9 Gy). V-95 was 96%, and D-95 was 65.75Gy. 33.3% of them received concurrent chemoradiotherapy. Results: Median overall survival (OS) was 21 months (1-93 mon). The 1-, 2-year local progression free survival (LPFS) rate was 84.5%, 64% and OS rate was 71.7%, 44.3%. Severe late adverse events (SLAE) occurred in 48.1% of patients, including 31.5% with ulcer or necrosis of the nasopharyngeal mucosa, 20.4% with difficulty in feeding, 18.5% with temporal lobe necrosis, 11.1% with massive hemorrhage. 15.4% died of local regional progression, 5.8% died of distant metastasis, 25% died of SLAE, 9.6% died of both local regional progression and SLAE that could not be differentiated, 5.8% died of other medical complications. Concurrent chemoradiotherapy was the independent negative prognostic factors for LPFS; PTV>100 ml was a predictive factor of poor OS; patients with invasion of post-styloid space were at higher risk of SLAE. Conclusions: The present study demonstrated that IMRT with 70Gy was efficient for local tumor control. However, we observed a high frequency of serious late complications. More optimized combination treatment and patient selection are required to achieve excellent local control without significant late morbidities in locally recurrent NPC.