Clinical use of molecular targeted agents for primary small bowel adenocarcinoma: A multicenter retrospective cohort study by the Osaka Gut Forum.

Primary small bowel adenocarcinoma (SBA) is a rare cancer for which effective treatment strategies have not yet been established. The results of previous retrospective studies suggest that chemotherapy contributes to a longer survival time in patients with SBA. However, there are few case reports about the efficacy of molecular targeted agent-containing chemotherapy for SBA. In the present study, the treatment and follow-up data of patients with SBA who received chemotherapy with or without molecular targeted agents were retrospectively analyzed. Each patient was treated in one of ten hospitals participating in the Osaka Gut Forum between April 2006 and March 2014. The following factors were evaluated: Age, sex, Eastern Cooperative Oncology Group performance status (PS), tumor location, tumor differentiation, chemotherapy regimen, resection of primary tumor, tumor biomarker expression, distant metastasis, best response under chemotherapy, time to disease progression, subsequent treatments, survival status and treatment toxicity. A total of 27 patients (17 males and 10 females; mean age, 63.4 years old; range, 36-83 years old) received chemotherapy due to non-curative tumor resection, unresectable tumor or post-operative recurrence. The median overall survival time was 14.8 months (range, 2-58 months). A univariate analysis revealed a PS of 0 (P=0.0228) and treatment with platinum-based chemotherapy (P=0.0048) were significant factors for an improved prognosis. An age-adjusted multivariate analysis also revealed that a platinum-based regimen was a significant positive prognostic factor (P=0.0373). Molecular targeted agents were administered to 8 patients, for whom it was their first- or second-line therapy. Among the 17 patients who received oxaliplatin-based chemotherapy as a first-line chemotherapy, a PS of 0 (P=0.0255) and treatment with bevacizumab (P=0.0121) were significant positive prognostic factors. Toxicities higher than Grade 3 occurred in 8/27 patients with SBA; however, serious side effects due to the molecular targeted agents were not experienced. The results of the present study indicate that chemotherapy containing molecular targeted agents is a well-tolerated and effective treatment option for SBA.