Is primary tumor volume still a prognostic factor in intensity modulated radiation therapy for nasopharyngeal carcinoma?

• Published in: Radiotherapy and oncology Vol. 104; no. 3; pp. 294 - 299
• Main Authors: Guo, Rui, Sun, Ying, Yu, Xiao-Li, Yin, Wen-Jing, Li, Wen-Fei, Chen, Yuan-Yuan, Mao, Yan-Ping, Liu, Li-Zhi, Li, Li, Lin, Ai-Hua, Ma, Jun
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.09.2012
• Subjects: Adult; Aged; Carcinoma; Cisplatin - administration & dosage; Female; Hematology, Oncology and Palliative Medicine; Humans; Intensity modulated radiotherapy; Male; Middle Aged; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms - mortality; Nasopharyngeal Neoplasms - pathology; Nasopharyngeal Neoplasms - radiotherapy; Neoplasm Staging; Primary tumor volume; Prognosis; Prognosis factor; Radiotherapy, Intensity-Modulated; Retrospective Studies; TNM stage; Tumor Burden; Nasopharyngeal carcinoma; Primary tumor volume; Prognosis factor; Intensity modulated radiotherapy; TNM stage
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2012.09.001

Abstract Background and purpose To evaluate the prognostic value of gross primary tumor volume (GTV-P) in nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiotherapy (IMRT). Methods and materials A total of 694 nonmetastatic and histologically proven NPC patients who underwent IMRT were retrospectively reviewed. Samples were split randomly into a training set ( n = 232) and a test set ( n = 462) to analysis. The receiver operating characteristic (ROC) curves were calculated to identify the cut-off point and test the prognostic validity of the GTV-P. The correlations between GTV-P and the American Joint Committee on Cancer (AJCC) disease stages were also analyzed. Results The 5-year disease-free survival (DFS), overall survival (OS), local relapse-free survival (LRFS) and distant metastasis-free survival (DMFS) rates for NPC patients with GTV-P < 19 vs. ⩾19 ml were 94.9% vs. 64.8%, 97.0% vs. 76.4%, 98.2% vs. 92.5% and 97.1% vs. 75.2%, respectively (all P < 0.05) in all patients. Multivariate analysis indicated GTV-P was an independent prognostic factor. The ROC curve verified that the predictive ability of T classifications was improved when combined with GTV-P ( P < 0.001). Conclusions GTV-P is an independent prognostic indicator for treatment outcome after IMRT, and significantly improves the prognostic validity of T classifications in NPC.