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<0.001) in multivariate analysis. In the large tumor volume group (PTV>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 <or= 15 mL), this phenomenon was not observed.


CONCLUSIONS
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.
Chu
Sau-Tung
ST
Department of Otolaryngology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC.
Wu
Pi-Hsiung
PH
Hou
Yu-Yi
YY
Chang
Kuo-Ping
KP
Chi
Chao-Chuan
CC
Lee
Ching-Chih
CC
D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies