Efficacy of adjuvant chemotherapy/maintenance chemotherapy after induction chemotherapy and concurrent chemoradiotherapy in patients with locoregionally advanced nasopharyngeal carcinoma: Experiences of two centers.

Background And Objective: In general, there are not many studies exploring the clinical value of adjuvant chemotherapy or maintenance chemotherapy (AC/MC) after induction chemotherapy and concurrent chemoradiotherapy (IC+CCRT+AC/MC). The purpose of this study was to establish a clinical nomogram for the use of AC/MC in patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC).

Material And Methods: Two centers (Guangzhou Medical University Cancer Center [N = 1226] and Zhongshan People's Hospital [N = 150]) recruited 1376 patients with LA-NPC. All the patients underwent IC+CCRT; 560 patients received AC with cisplatin/nedaplatin plus docetaxel/paclitaxel (TP) or cisplatin/nedaplatin plus fluorouracil (PF), and 81 patients received MC with S-1. Multivariate Cox regression was used to confirm optimal predictors of progression-free survival (PFS), and a nomogram was established to identify patients into low-risk and high-risk cohorts. Additionally, bootstrap internal validation was performed to further verify our nomogram.

Results: After propensity score matching (PSM), the survival curves were not statistically different between IC+CCRT+AC/MC and IC+CCRT (all p > 0.05). Then, a nomogram was developed based on variables that were screened by univariate and multivariate Cox regression, including N stage, cumulative platinum dose during CCRT, body mass index (BMI), IC cycles, IC regimen and cervical lymph node (CLN) necrosis and infiltration of adjacent tissues. The results of the nomogram showed that the high-risk cohort had greatly worse 5-year DMFS, LRFS, PFS and OS compared to low-risk cohort (all p < 0.05), and subgroup analysis found that the 5-year DMFS, PFS and OS of patients treated with IC+CCRT+AC/MC were better than those treated with IC+CCRT in high-risk cohort (all p < 0.05). Notably, the incidence of adverse effects for IC+CCRT+AC cohort was higher than that for IC+CCRT+MC cohort, especially leukocytopenia and neutropenia. IC+CCRT and IC+CCRT+MC were associated with similar incidences of adverse effects.

Conclusions: The addition of AC or MC to IC+CCRT could improve the DMFS of patients with high-risk NPC and prolong their survival. Additionally, our findings suggest a potential role of AC/MC following IC plus CCRT in the treatment of high-risk LA-NPC.