Validation of published nomograms and accordingly individualized induction chemotherapy in nasopharyngeal carcinoma.

OBJECTIVES

We have attempted to validate two published nomograms in nasopharyngeal carcinoma (NPC) and individualize induction chemotherapy (IC) accordingly.

MATERIALS AND METHODS

From 2007 to 2011, 920 patients were included in the study. The validity of the nomograms was assessed by Harrell's concordance index (C-index), areas under the curve (AUC), and calibration curves. Disease-free survival (DFS) and overall survival (OS) by IC were evaluated in and out of risk stratified patients with and without propensity score matching analysis.

RESULTS

Compared with the 7th edition of the Union for International Cancer Control (UICC) staging system, Tang's nomogram better discriminated DFS (C-index 0.629 versus 0.569, P=0.002; AUC 0.635 versus 0.576, P=0.018), whereas Yang's nomogram had no advantage in predicting OS (C-index 0.648 versus 0.606, P=0.184; AUC 0.643 versus 0.604, P=0.157). Calibration curves indicated good agreement between predicted and observed DFS or OS probability. Without risk stratification, patients achieved no benefit from IC in DFS (P⩾0.101) or OS (P⩾0.370). However, among 580 high-risk patients stratified by Tang's nomogram, IC improved five-year DFS from 68.8 to 74.8% (P=0.072), and OS from 82.6 to 87.9% (P=0.065), and the improvement of DFS and OS increased to 9.3% (P=0.019) and 7.3% (P=0.036), respectively, in 426 propensity-matched patients.

CONCLUSIONS

Tang's nomogram helps to stratify stage III-IVa-b NPC, and IC is beneficial to high-risk patients in clinical practice.