A phase I dose escalation study of S-1 with concurrent radiotherapy in elderly patients with esophageal cancer

Background

Concurrent chemoradiotherapy (CRT) with 5-fluorouracil (5-FU) and cisplatin (CDDP) are often associated with significant incidence of toxic effects in elderly patients with esophageal cancer. This phase I trial was designed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of S-1, an oral 5-FU derivative, when given with radiotherapy in elderly patients.

Methods

Patients who were age of 70 years or older with histologically confirmed esophageal cancer, and had an Eastern Cooperative Oncology Group (ECOG) score of 0–2 were eligible for this study. Radiotherapy was administered in 1.8 Gy fractions 5 times weekly to a total dose of 54 Gy. S-1 was administered on days 1–14 and 29–42 at the following dosages: 60, 70, and 80 mg/m²/day. Trial registration: {"type":"clinical-trial","attrs":{"text":"NCT01175447","term_id":"NCT01175447"}}NCT01175447 (ClinicalTrials.gov).

Results

Twelve previously untreated patients were enrolled in this study. No grade 3 or 4 toxicity was observed in six patients treated at the 60 and 70 mg/m² dose levels. DLT was observed in four of six patients treated at the 80 mg/m² dose level. Two patients developed grade 3 esophagitis, one patient developed grade 3 esophagitis and pneumonitis, and one patient developed grade 3 thrombocytopaenia. Endoscopic complete response (CR) was observed in eight patients (66.7%). The median progression free survival (PFS) was 20 months and median overall survival was 29 months.

Conclusions

The MTD of S-1 was 80 mg/m², and the recommended dose (RD) for phase II studies was 70 mg/m². This regimen was well tolerated and active in elderly patients with esophageal cancer, meriting further investigation in phase II studies.