Prognostic factors of 305 nasopharyngeal carcinoma patients treated with intensity-modulated radiotherapy

Abstract

Radiotherapy is effective in treating nasopharyngeal carcinoma (NPC). This study evaluated the treatment efficacy, toxicity, and prognostic factors of intensity-modulated radiotherapy (IMRT) in the treatment NPC. Between September 2003 and September 2006, 305 patients with NPC were treated with IMRT in Fujian Provincial Cancer Hospital. IMRT was delivered as follows: gross tumor volume (GTV) received 66.0-69.8 Gy in 30-33 fractions, high-risk clinical target volume (CTV-1) received 60.0-66.65 Gy, low-risk clinical target volume (CTV-2) and clinical target volume of cervical lymph node regions (CTV-N) received 54.0-55.8 Gy. Patients with stages III or IV disease also received cisplatin-based chemotherapy. All patients were assessed for local-regional control, survival, and toxicity. With a median follow-up of 35 months (range, 5-61 months), there were 16, 8, and 39 patients who had developed local, regional, and distant recurrence, respectively. The 3-year rates of local control, regional control, metastasis-free survival, disease-free survival, and overall survival were 94.3%, 97.7%, 86.1%, 80.3%, and 89.1%, respectively. Multivariate analyses revealed that T-classification had no predictive value for local control and survival, whereas N-classification was a significant prognostic factor for overall survival (P < 0.001), metastasis-free survival (P < 0.001), and disease-free survival (P = 0.003). For stages III-IV disease, concurrent and adjuvant chemotherapy did not influence prognosis. The most severe acute toxicities included Grade III mucositis in 14 patients (4.6%), Grade III skin desquamation in 90 (29.5%), and Grades III-IV leucocytopenia in 20 (6.5%). There were 7% patients with Grade II xerostomia after 2 years of IMRT, no Grades 3 or 4 xerostomia was detected. IMRT provided favorable locoregional control and survival rates for patients with NPC, even in those with locally advanced disease. The acute and late toxicities were acceptable. N-classification was the main factor of prognosis. Further study is needed on chemotherapy for patients with NPC.