Phase II trial of adjuvant chemotherapy with S-1 for colorectal liver metastasis.

Background: This phase II trial was designed to evaluate the safety and efficacy of adjuvant chemotherapy with S-1 in patients with curatively resected liver metastasis from colorectal cancer. Results of an interim analysis of safety and short-term outcomes are reported.

Methods: Patients who underwent curative resection of liver metastasis from colorectal cancer received S-1 monotherapy (on days 1-28, followed by 14 days' rest, 8 cycles) as adjuvant chemotherapy.

Results: Among 62 patients enrolled between October 2008 and August 2010, a total of 60 patients were eligible for analysis. The most frequent grade 3 or higher hematologic toxicity involved neutropenia in three patients (5.0 %). Nonhematologic toxicities of grade 3 or higher were fatigue in 6.7 % of patients. Grade 4 enteritis occurred in one patient, but resolved promptly after withdrawal of S-1 therapy. The completion rate of the eight scheduled cycles of chemotherapy was 58.3 %. The most common reasons for withdrawal of treatment was the detection of early relapse in 16 patients (64 %). When the 16 patients who had recurrence during adjuvant treatment were excluded from analysis, 79.5 % of the remaining 44 patients completed the scheduled treatment. Early recurrence within 1 year after curative liver resection occurred in 21 patients (35 %). The most common site was the remnant liver in 14 patients.

Conclusions: Orally administered S-1 after curative liver resection has an acceptable toxicity profile and a high rate of completion of the therapy. S-1 can be safely used and might be a viable treatment option in an adjuvant setting.