This Phase I study looked at using S-1 plus oxaliplatin as consolidation chemotherapy after chemoradiotherapy for stage II or III lower rectal adenocarcinoma. The research involved 12 patients. The team wanted to see if this treatment was safe and well tolerated before testing it more widely.
One dose-limiting toxicity occurred at the first dose level, but none happened at the second level. Grade 3 hematologic toxicities like leukopenia and neutropenia were seen in three patients at the second dose level. However, there were no non-hematologic adverse events with grade 3 or higher. Overall, the treatment was considered safe and well tolerated.
All 12 patients underwent surgery within the planned timeframe. One patient experienced a postoperative complication of Clavien-Dindo grade 2 or higher. This was the first study to report using this specific combination for this cancer type. Because the sample size is small and the design is Phase I, further trials are needed to evaluate efficacy in larger populations. Results are not generalizable to larger groups without more research.