The Study of Clinical Prognostic Factors in Nasopharyngeal Carcinoma after Intensity Modulated Radiation Therapy

Objective: The objective of this study is to identity the prognostic factor of NPC patients ereated with IMRT retrospectively with the hope of prognosis prediction and providing better treatment. Methods: From January, 2004 to August, 2006, 137 consecutive patients with histology-proven non-metastatic NPC were registered at the Cancer Hospital, Xinjiang, medical university. All patients received CT(computed tomography ) or MRI (magnetic resonance imaging) scan before treatment. The clinical staging was reassessed by the 1992 Fuzhou staging system according to CT or MRI and clinical informations. The endpoint of this study was overall survival OS, relapse-free survival RFS, distant metasis-free survival DMFS and disease-free survival DFS. Using Kaplan-Meier method to calculate overall survival rate, relapse-free survival rate, distant metasis-free survival rate and disease-free survival rate. Differences between 14 potential prognostic factor were tested for statistical significance by the Log-rank test, P<0.05 as the significance limit. Multivariate analysis was performed with the Cox regression model to identify independent prognostic factors. Result: Of the 137 cases the1-year, 3-year and 5-year overall survival rates were 98.5%, 90.3%, 74.6%, relapse-free survival rates were 97.0%, 81.9%, 66.7%;distant metasis-free survival rates were 96.3%, 80.5%, 56.0%;disease free survival rates were:95.6%, 76.9%, 43.8%. Univariate analysis revealed that the influence of T-classification, N-classification, the clinical staging, chemotherapy, residual disease, total time of IMRT, anemia, retropharyngeal lymph node metastasis, cranial nerve palsy and base of the skull bone were of statistical significant, Multivariate analysis only revealed that N-classification, chemotherapy, residual disease, total time of IMRT, and cranial nerve palsy were significant independent predictors for survival. Conclusion: Our study demonstrated that IMRT may improve the survival rate of non-metastatic NPC patients. IMRT of NPC after N-classification, cranial nerve palsy, chemotherapy, residual disease, total time of IMRT is the most main factors affect prognosis.