Ten-year experience of radical radiotherapy for nasopharyngeal carcinoma: analysis of 905 patients

Objective: To report our experience of radical radiotherapy for nasopharyngeal carcinoma (NPC) in our institution during the last decade. Methods: From January 1990 to May 1999, 905 NPC patients were treated and studied retrospectively. The impact of boost irradiation to the residual tumor after 70-72 Gy extemal beam radiotherapy(EBRT) on the treatment results, the pattern of failure and related prognostic factors were summarized. Results: The 5- and 10-year local-regional control, overall survival and disease-free survival rates were 81.7% and 76.7%, 76.1% and 66.5%, 58.4% and 52.1%, respectively. For residual primary lesion after a dose of 70-72 Gy of conventional EBRT, an additional boost was able to achieve a local control of 80.8 %, similar to that obtained with primary lesion which had completely disappeared at 70-72 Gy(82.6 %, P 0.892). Age, Kamovsky performance status, pretreatment hemoglobin level, T and N stage were shown to be prognostic factors for overall survival and disease-free survival. On univariate analysis, age, T and N stage and clinical stage were independent factors for local control and disease-free survival, whereas T and N stage were independent factors for overall survival. T4 and N3 stage were predictive for distant metastasis (P<0.05), of which bone was the most common site,followed by liver and lung. Conclusions: The treatment results of radical external beam radiotherapy followed by a boost irradiation to the residual primary tumor for nasopharyngeal carcinoma in our institution are promising. Local-regional relapse and distant metastasis were the major cause of failure, especially for the T4 and N3 stage patients. Early diagnosis and improvement of the outcome for locally advanced lesion are the main goal of our further clinical research. (authors)