Administration of oral maintenance chemotherapy for 1 year following definitive chemoradiotherapy may improve the survival of patients with stage N3 nasopharyngeal carcinoma.

OBJECTIVES

This study aims to evaluate the effectiveness and the optimal maintenance period of oral chemotherapy using S1 following definitive chemoradiotherapy in patients with stage N3 nasopharyngeal carcinoma (N3-NPC).

MATERIALS AND

METHODS

A retrospective review was performed for N3-NPC treatment with maintenance chemotherapy (MC) [chemoradiotherapy (CRT)-MC] or without MC (CRT-non-MC) following definitive CRT between May 2014 and December 2017. Toxicities during MC were recorded. Overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS) and locoregional relapse-free survival (LRRFS) were compared between CRT-MC and CRT-non-MC cohorts. The optimal duration of using maintenance S1 (MC-S1) was also analyzed.

RESULTS

A total of 304 patients with stage N3-NPC were identified, of whom 56 were treated with CRT-MC and 248 with CRT-non-MC. After a median follow-up of 48 months, significant differences in OS (74.9 vs. 91.7%; P = 0.003), PFS (60.7 vs. 83.7%; P = 0.001) and DMFS (68.8 vs. 85.5%; P = 0.015) were observed between the CRT-non-MC and CRT-MC groups. Skin hyperpigmentation, leukopenia and fatigue were common but not severe (grade 1-2) side effects of MC. The OS, DMFS and PFS were significantly higher for patients who received S1 administration over a period of ≥12 cycles compared with those who received <12 cycles (3-year OS, 100 vs. 87.5%, P = 0.018; 3-year PFS, 93.9 vs. 67.9%, P = 0.006; 3-year DMFS, 97.1 vs. 67.9%, P = 0.002).

CONCLUSIONS

Using MC-S1 in patients with N3-NPC following definitive chemoradiotherapy achieved superior survival rate compared with the patients with non-MC. The side effects of MC-S1 were mild and tolerable. S1 should be maintained for ≥12 cycles.