Primary Tumor Volume of Nasopharyngeal Carcinoma: Significance for Recurrence and Survival

Background: Primary tumor volume (PTV) is known to be a significant prognostic factor in malignant tumor. There have been several studies of nasopharyngeal carcinoma (NPC) relating tumor volume to treatment outcome. Our study was designed to evaluate the effect of PTV on treatment outcomes in NPC treated with radiotherapy (RT)/concurrent chemoradiotherapy (CCRT) or CCRT with adjuvant chemotherapy. Methods: We retrospectively reviewed 100 cases with newly diagnosed NPC who were treated with RT/CCRT or CCRT with adjuvant chemotherapy from 2002 to 2006. Magnetic resonance imaging-derived PTV was calculated using the summation-of-area technique. Kaplan-Meier plots and the log-rank test were used to estimate tumor recurrence (locoregional, distant, or both) and overall survival. Cox proportional hazards regression analysis was used to assess the prognostic impact of PTV. Results: The median PTV was 12.94 mL. PTV remained an independent prognostic factor for distant metastasis (hazard ratio [HR], 1.04; p = 0.03), for any relapse (HR, 1.04; p = 0.02), and for overall survival (HR, 1.09; p 15 mL), patients’ metastasis-free survival rates, with and without adjuvant chemotherapy, were 100% and 68.3%, respectively (p = 0.002). Their 3-year recurrence-free survival rates, with and without adjuvant chemotherapy, were 94.1% and 69.6%, respectively (p = 0.006). In the small tumor volume group (PTV ≤ 15 mL), this phenomenon was not observed. Conclusion: PTV had a close relationship with survival rates and recurrence rates in patients with NPC. The large tumor volume group (PTV > 15 mL) was associated with more recurrence and poor survival rate, and it was suggested that these high-risk patients should benefit from CCRT followed by adjuvant chemotherapy. [J Chin Med Assoc 2008;71(9): 461–466]