Chemoradiotherapy Versus Radiotherapy Alone in Stage II Nasopharyngeal Carcinoma: A Systemic Review and Meta-analysis of 2138 Patients.

To explore the value of chemoradiotherapy (CRT) in stage II nasopharyngeal carcinoma (NPC) compared to radiotherapy (RT) alone which includes two-dimensional radiotherapy (2D-RT) and intensity-modulated radiotherapy (IMRT). All topic-related comparative articles were identified by a comprehensive search of public databases (MEDLINE, EMBASE, Cochrane Library and CBMdisc). The primary outcomes were overall survival (OS), loco-regional relapse-free survival (LRRFS) and distant metastasis-free survival (DMFS). Secondary outcomes were grade 3-4 acute toxicity events. We performed subgroup analysis of CRT versus 2D-RT/IMRT alone to investigate the optimal modality. Sensitivity analysis focused on CRT versus IMRT alone was used to assess stability of the study results. Eleven comparative studies (2138 patients) were eligible. CRT had significantly higher OS (HR = 0.67, 95% CI = 0.45-0.98, = 0.04) and LRRFS (HR = 0.61, 95% CI = 0.46-0.80, = 0.0003) than RT alone, but no significant difference was observed in DMFS (HR = 0.83, 95% CI = 0.52-1.31, = 0.41). Meanwhile, CRT was associated with higher frequencies of grade 3-4 leukopenia, mucositis and nausea ( = 0.005, 0.03, < 0.0001, respectively). Subgroup analysis showed that IMRT alone could achieve equivalent OS, LRRFS and DMFS compared to CRT ( = 0.14, 0.06, 0.89, respectively). Significant value was only observed in LRRFS for CRT compared to 2D-RT alone ( = 0.01). Sensitivity analysis for the comparison of CRT and IMRT alone demonstrated generally stable outcomes, in support of the final conclusions. In the treatment of patients with stage II NPC, CRT was better than 2D-RT alone with significant benefit in LRRFS. IMRT alone was superior to CRT with equivalent survival outcomes and fewer grade 3-4 acute toxicities.