Necessity of concurrent chemotherapy in N2-3 nasopharyngeal carcinoma treated with neoadjuvant chemotherapy of ≥3 cycles followed by intensity-modulated radiotherapy.

Concurrent chemotherapy (CCT) is used in locally advanced nasopharyngeal carcinoma (NPC) for improved local control, which could also be achieved by intensity-modulated radiotherapy (IMRT). And for N2-3 NPC, distant metastasis is the more important cause of death. This study aims to evaluate the value of CCT in N2-3 NPC when neoadjuvant chemotherapy (NACT) of sufficient cycles is performed to eradicate distant metastasis. It enrolled 959 patients diagnosed with TxN2-3M0 NPC from July 2011 to December 2015 and treated with NACT of 3-4 cycles and IMRT. A propensity score matching (PSM) was made between patients treated with and without CCT (called the CCT and non-CCT groups, respectively), using a series of clinical characteristics (age, gender, T stage, N stage, NACT regimen, and EBV DNA) as covariates. After PSM, the two groups of patients were compared on survivals and acute toxicities. The results indicated that no difference was seen in the overall, disease-free, recurrence-free or metastasis-free survivals between the two groups. But compared with the CCT group, the non-CCT group had a lower patient proportion of myelosuppression, nausea/vomiting, oral mucositis, cervical dermatitis, xerostomia, and grade 3/4 myelosuppression and oral mucositis (all P values were <0.001). Hence, CCT appeared to bring more acute toxicities, instead of survival benefit, to N2-3 NPC patients treated with NACT of ≥3 cycles and IMRT. It should be used with cautions in these patients.