An Analysis on Factors Affecting Local Control and Survival in Nasopharyngeal Carcinoma / 대한방사선종양학회지

ABSTRACT

PURPOSE: This study was performed to find out the prognostic factors affecting local control, survival and disease free survival rate in nasopharyngeal carcinomas treated with chemotherapy and radiation therapy. MATERIALS AND METHODS: We analysed 47 patients of nasopharyngeal carcinomas, histologically confirmed and treated at Chonnam University Hospital between July 1986 and June 1996, retrospectively. Range of patients' age were from 16 to 80 years (median; 52 years). Thirty three (70%) patients was male. Histological types were composed of 3 (6%) keratinizing, 30 (64%) nonkeratinizing squamous cell carcinoma and 13 (28%) undifferentiated carcinoma. Histological type was not known in 1 patient (2%). We restaged according to the staging system of 1997 American Joint Committee on Cancer. Forty seven patients were recorded as follows T1; 11 (23%), T2a; 6 (13%), T2b; 9 (19%), T3; 7 (15%), T4; 14 (30%), and N0; 7 (15%), N1; 14 (30%), N2; 21 (45%), N3; 5 (10%). Clinical staging was grouped as follows Stage I; 2 (4%), IIA; 2 (4%), IIB; 10 (21%), III; 14 (30%), IVA; 14 (30%) and IVB; 5 (11%). Radiation therapy was done using 6 MV and 10 MV X- ray of linear accelerator. Electron beam was used for the lymph nodes of posterior neck after 4500 cGy. The range of total radiation dose delivered to the primary tumor was from 6120 to 7920 cGy (median; 7020 cGy). Neoadjuvant chemotherapy was performed with cisplatin+5-fluorouracil (25 patients) or cisplatin+pepleomycin (17 patients) with one to three cycles. Five patients did not received chemotherapy. Local control rate, survival and disease free survival rate were calculated by Kaplan-Meier method. Generalized Wilcoxon test was used to evaluate the difference of survival rates between groups. Multivariate analysis using Cox proportional hazard model was done for finding prognostic factors. RESULTS: Local control rate was 81% in 5 year. Five year survival rate was 60% (median survival; 106 months). We included age, sex, cranial nerve deficit, histologic type, stage group, chemotherapy, elapsed days between chemotherapy and radiotherapy, total radiation dose, period of radiotherapy as potential prognostic factors in multivariate analysis. As a result, cranial nerve deficit (P=0.004) had statistical significance in local control rate. Stage group and total radiation dose were significant prognostic factors in survival (P=0.006, P=0.012), and in disease free survival rates (P=0.003, P=0.008), respectively. Common complications were xerostomia, tooth and ear problems. Hypothyroidism was developed in 2 patients. CONCLUSION: In our study, cranial nerve deficit was a significant prognostic factor in local control rate, and stage group and total radiation dose were significant factors in both survival and disease free survival of nasopharyngeal carcinoma. We have concluded that chemotherapy and radiotherapy used in our patients were effective without any serious complication.