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

Abstract

Background and objective: 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.

Methods: 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.

Results: 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.

Conclusions: 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.