Prognosis analyses of 133 nasopharyngeal carcinoma from northwest China treated by intensity-modulated radiotherapy

Objective: To evaluate the long term outcomes, toxicities and prognostic factors of the patients in Northwest China with nasopharyngeal carcinoma (NPC) treated by intensity-modulated radiotherapy (IMRT). Methods: From January 2006 to December 2009, 133 NPC Patients were treated by IMRT in Xijing Hospital, the Fourth Military Medical University. There were 22 treated by radiotherapy alone, 111 treated by platinum-based current chemoradiotherapy. The prescription dose to the gross tumor volume was 66 - 76.6 Gy/30 - 33 fractions, positive lymph nodes was 66. 0 - 72.4 Gy/30 - 33 fractions. The higher and lower risk clinical target volume were irradiated with 56.0 - 63.5 Gy/28 - 33 fractions and 50.4 -53.2 Gy/28 fractions respectively. Results: The follow-up rate was 97.7%. Follow-up time more than 2 years, 3 years were 37 cases, 44 cases. The l-, 2-and 3-year overall survival (OS) were 93.8%, 88.3% and 83.2%; local control rate were 99.2%, 95.4% and 95.4%; regional control rate (RC) were 99.2%, 96.8% and 96.8%; and distant metastasis-free rate (DMFR) were 82.8%, 79.8% and 79.8%; the disease-free survival (DFS) were 84.3%, 76.7% and 76.7%, respectively. Multivariate analyses revealed that N stage, age and anemia before radiotherapy were independent predictors for OS (χ2 =5.56, 9.10, 4.89, P=0.018, 0.003, 0.027), and N stage was also independent predictors for DFS (χ2 =8.98, P=0.003). The grade 3 acute toxicities were mucositis (34.7%), xerostomia (20.1%), skin reaction (1.4%) and leucocytopenia (1.4%). No grade 4 acute and late toxicities were detected. Conclusions: IMRT with or without chemotherapy achieved good long term survival in nasopharyngeal carcinoma treated by intensity-modulated radiotherapy, especially in LC and RC. Distant metastasis becomes the main treatment failure. N stage, age, and anemia before radiotherapy were the main prognostic factors in nasopharyngeal cancer patients. (authors)