Purpose: We used randomized trials of radiotherapy (RT) with or without chemotherapy in non-metastatic nasopharyngeal carcinoma to investigate the survival benefit of chemoradiotherapy regimens between two/three-dimensional radiotherapy (2D/3D RT) and intensity-modulated radiotherapy (IMRT). Methods: Overall, 27 trials and 7,940 patients were included. Treatments were grouped into seven categories including RT alone, induction chemotherapy (IC) followed by RT (IC-RT), RT followed by adjuvant chemotherapy (RT-AC), IC followed by RT followed by AC (IC-RT-AC), concurrent chemo-radiotherapy (CRT), IC followed by CRT (IC-CRT), and CRT followed by AC (CRT-AC). To distinguish between 2D/3D RT and IMRT, three categories in IMRT were newly added, including CRT in IMRT, IC-CRT in IMRT, and CRT-AC in IMRT. The P score was used to rank the treatments. Results: Both fixed- and random-effects frequentist and Bayesian network meta-analysis models were applied, which provided similar results and the same ranking. IC-CRT was the most effective regimen compared with CRT-AC and CRT in the IMRT era for overall survival (OS) (HR, 95% CI, IC-CRT vs. CRT-AC, 0.61 (0.45, 0.82); IC-CRT vs. CRT 0.65 (0.47, 0.91)), progression-free survival (PFS) (0.69 (0.54, 0.88); 0.63 (0.49, 0.80)), and distant metastasis-free survival (DMFS) (0.58 (0.28, 1.21); 0.60 (0.42, 0.85)). CRT-AC achieved the highest survival benefit compared with CRT, and IC-CRT for loco-regional relapse-free survival (LRRFS) (0.44 (0.15, 1.28); 0.72 (0.22, 2.33)). Among these 10 categories, after distinguishing between 2D/3D RT and IMRT, IC-CRT in IMRT ranked first for OS, PFS, and DMFS, and CRT-AC in IMRT ranked first for LRRFS. Conclusion: IC-CRT should be the most suitable regimen for loco-regionally advanced NPC in the IMRT era.
Keywords: chemotherapy; intensity-modulated radiotherapy; nasopharyngeal carcinoma; network meta-analysis; radiotherapy; survival outcome.