Reirradiation of nasopharyngeal carcinoma withintensity-modulated radiotherapy

Abstract

Background and purpose To evaluate the treatment outcome in patients with locally recurrent nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Materials and methods Between October 2001 and May 2004, 31 patients with locally recurrent NPC received reirradiation using IMRT. The rT classification distribution was 3 for rT1, 5 for rT2, 9 for rT3, and 14 for rT4. Median time from first course of radiotherapy to reirradiation was 51 months. IMRT was performed using step-and-shoot method with nine 4–6 MV photon fields and median prescribed dose was 54 Gy (range: 50–60 Gy). Additional treatments included cisplatin-based induction chemotherapy in 68% and radiosurgery boost with a single dose which ranged from 8.5 to 12.5 Gy in 32%. Median follow-up time was 11 months. Results After reirradiation, 58% of patients had complete regression of primary tumor. One-year loco-regional progression-free, distant metastasis-free and overall survival rates were 56, 90, and 63%, respectively. Significantly better 1-year local progression-free rate was observed in rT1–3 than rT4 tumor (100 vs. 35%). Grade 3 late toxicities, mostly ototoxicity/cranial neuropathy, occurred in six patients (19%). One-year actuarial rates of late toxicities were 70% for all grades and 25% for Grade 3. Conclusion Our preliminary results showed that good control of rT1–3 NPC can be achieved using IMRT with a dose between 50 and 60 Gy, whereas the outcome for rT4 tumor remained poor. Late toxicities were common but incidence of severe toxicities was relatively low.