Objectives: Radiation Therapy Oncology Group study 91-11 found that in resectable advanced laryngeal cancer, the locoregional control rate achieved with reduced intra-arterial cisplatin and concurrent radiotherapy (RADPLAT) was comparable to that of a concurrent chemoradiotherapy arm, with reduced toxicities. However, distant metastases were more frequent. Our study retrospectively evaluated the efficacy and feasibility of adjuvant chemotherapy with S-1, an oral fluoropyrimidine, for distant metastases following reduced RADPLAT.
Methods: We analyzed 61 patients who were treated with reduced RADPLAT and achieved a complete response at the primary site. After the use of reduced RADPLAT, 24 patients were administered S-1 for 2 weeks followed by 1 week of rest, and the cycle was repeated for 6 months (S-1+ group). Thirty-seven patients were not administered S-1 (S-1-group).
Results: The hazard ratio for distant metastases in the S-1+ group was 0.114 (95% confidence interval, 0.015 to 0.881; p = 0.0374). There was a significant difference in disease-free survival in favor of the S-1+ group (p = 0.0455). Nineteen patients (79.2%) in the S-1+ group received S-1 according to the planned schedule and dose. Grade 3 toxicities were observed in 2 patients (8.3%), but there was no grade 4 event.
Conclusions: In resectable advanced laryngeal cancer, S-1 adjuvant chemotherapy is an effective and feasible treatment option to control distant metastases following reduced RADPLAT.