The effect of primary tumor volumes in advanced T-staged nasopharyngeal tumors.

Background Tumor volume is an important prognostic factor in patients with malignancy treated with primary radiotherapy. It is necessary to have a clear understanding of the nasopharyngeal primary tumor volume and the treatment outcome, especially in the advanced T-staged tumors. Methods From 1994–1996, 76 newly diagnosed patients with advanced T-staged nasopharyngeal carcinomas who were treated with high-dose radiotherapy with or without chemotherapy were included in this study. CT-derived primary tumor volume was obtained after the summation of area technique. Results The median primary tumor volume was 29.6 mL in T3 disease and 54.1 mL in T4 disease, with a range of 8.0–131.8 in T3 disease, and 6.7–223.1 ml in T4 disease. Large primary tumor volume was associated with a significantly poor disease-specific survival (p < .0001), whereas the T stage carried no prognostic significance (p = .43). Conclusions In advanced T-staged (T3 and T4) nasopharyngeal tumors, a substantial variation of primary tumor volume was present within the same T stage, and primary tumor volume represented a more important prognostic factor for treatment outcome. Volumetric measurements of primary tumors in advanced nasopharyngeal tumors would refine the TNM staging system. Patients with large primary tumor volume should be treated more aggressively. © 2002 Wiley Periodicals, Inc. Head Neck 24: 940–946, 2002