Prognostic significance of tumor volume in patients with nasopharyngeal carcinoma undergoing intensity-modulated radiation therapy.
BACKGROUND
This study was undertaken to analyze the correlation between primary gross tumor volume (GTVp) and prognosis in patients with nasopharyngeal carcinoma (NPC) undergoing intensity-modulated radiation therapy (IMRT).


METHODS
Between February 2001 and December 2006, 305 patients with NPC treated with IMRT were analyzed retrospectively. GTVp was calculated from treatment planning CT scans.


RESULTS
Univariate and multivariate analyses indicated that GTVp had a statistically significant correlation to local control, distant metastasis, and overall survival in patients with NPC, whereas T classification was not an independent prognostic factor. Among patients classified with N0-1 and N2-3, there were significant differences in the rates of distant metastasis between those with GTVp smaller and larger than 25 mL (p < .001 and p = .002, respectively).


CONCLUSIONS
GTVp is highly significant in evaluating local control, distant metastasis, and overall survival of patients with NPC treated with IMRT. Therefore, it is recommended that GTVp be included in the new TNM classification system.
Department of Radiation Oncology, State Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-sen University, Guangzhou, China.
Zheng
Z
Wu
Rui-Fang
RF
Zeng
Yong
Y
Su
Mo-Fa
MF
Gu
Shao-Min
SM
Huang
D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D011379:Prognosis; D012372:ROC Curve; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D016019:Survival Analysis; D055815:Young Adult