The effects of chemotherapy on primary small bowel cancer: A retrospective multicenter observational study in Japan

Small bowel cancer is relatively rare among gastrointestinal tract cancers, including esophageal, gastric and colorectal cancers. The majority of cases of small bowel cancer are diagnosed at an advanced stage, resulting in poor outcomes. The clinical effects of chemotherapy on small bowel cancer have been investigated in a limited number of studies from Europe and the USA. However, they have not yet been fully investigated in Asian countries, including Japan. This retrospective multicenter observational study was designed to investigate the efficacy of chemotherapy on small bowel cancer. A questionnaire survey was conducted in 28 hospitals affiliated with the Osaka University Hospital. We retrospectively reviewed the medical records of 61 patients with small bowel cancer (32 patients who were unable to undergo curative resection or had unresectable distant metastases and 29 who underwent curative resection), treated between 1996 and 2009, to evaluate the outcomes and the efficacy of chemotherapy. There was no significant difference in the overall survival between the patients undergoing curative resection with postoperative adjuvant chemotherapy and those without postoperative adjuvant chemotherapy. In patients with non-curative resection or unresectable distant metastases, the response rate to chemotherapy was 31.6% and the overall survival was significantly higher compared to that without chemotherapy (P=0.008). The study results suggested that chemotherapy is effective for Japanese patients with small bowel cancer who cannot undergo curative resection or have unresectable distant metastases.