Final Results Of A Phase Ii Study Of Definitive Chemoradiation Therapy Using S-1 For Esophageal Squamous Cell Carcinoma Patients

This study aimed to assess the safety and local control rate of S-1 (tegafur-gimeracil-oteracil potassium) combined with radiotherapy in locally advanced esophageal squamous cell carcinoma (ESCC) patients who reject or cannot tolerate intravenous chemotherapy. Locally advanced ESCC patients presented with stage Ib to IVa, who rejected or were intolerant to intravenous chemotherapy were enrolled in a prospective, single-arm, phase 2 trial. The patients were treated with definitive concurrent chemoradiotherapy with S-1, which was administered orally at a dose of 40 mg (BSA ≤ 1.6 m2) or 50 mg (BSA >1.6 m2) twice daily for 28 days. The radiotherapy dose was 61.2 Gy delivered in 34 fractions. The primary end-point was 3-yr local control rate. This trial was registered with ClinicalTrials.gov, number NCT01831531. One hundred five ESCC patients were recruited between Mar 2013 and Oct 2015. At the median follow-up of 48.4 months (range 3.7-68.4 months), 3-yr local control rate and 3-yr overall survival were 61.5% and 44.4%, respectively. For safety analysis, ≥Grade 3 adverse events included thrombocytopenia (6.7%), leukopenia (2.9%), pneumonitis (4.9%), anemia (1.0%), hiccup (1.0%), fatigue (3.8%), and esophagitis (1.0%). One patient (1.0%) died of pneumonitis. S-1 might be a promising regimen in concurrent chemoradiotherapy with low toxicity and favorable local control rate in ESCC patients who rejected or were intolerant to intravenous chemotherapy.