ABSTRACT
BACKGROUND: Alternate-day administration of S-1 is thought to reduce toxicities. This phase II study evaluated S-1 on alternate days combined with bevacizumab as first-line treatment for elderly patients with metastatic colorectal cancer. PATIENTS AND METHODS: Eligible patients had histologically proven colorectal adenocarcinoma, measurable metastatic lesions, age ≥ 75 years, Eastern Cooperative Oncology Group performance status ≤ 1, no previous chemotherapy, and refused oxaliplatin- or irinotecan-containing regimens. Patients received 40 mg, 50 mg, or 60 mg (body surface area ≤ 1.25 m2, > 1.25 to ≤ 1.50 m2, or > 1.50 m2, respectively) of S-1 twice orally on Sunday, Monday, Wednesday, and Friday every week. Bevacizumab (7.5 mg/kg) was administered every 3 weeks. The primary endpoint was progression-free survival. RESULTS: Of 54 enrolled patients, 50 patients were evaluated for efficacy and 53 for safety. The median age was 79 years (range 75-88 years). The median progression-free survival was 8.1 months (95% confidence interval (CI) 6.7-9.5 months). The median overall survival was 23.1 months (95% CI 17.4-28.8 months). The response rate was 44% (95% CI 30.2-57.8%), and the disease control rate was 88% (95% CI 79.0-97.0%). Grade 3 or higher hematologic, non-hematologic, and bevacizumab-related adverse events occurred in 9%, 11%, and 25% of patients, respectively. The most common grade 3 and 4 treatment-related adverse events were hypertension (11%), nausea (6%), fatigue (6%), anemia (6%), and proteinuria (6%). Only 6 patients discontinued treatment due to adverse events. CONCLUSION: S-1 on alternate days combined with bevacizumab showed better tolerability and comparable survival compared with the results of similar studies.
