Meta-analysis of postoperative adjuvant therapy for small bowel adenocarcinoma

Objective: The role of adjuvant therapy in small bowel adenocarcinoma (SBA), a rare malignancy with a poor prognosis, is controversial. The purpose of this article is to investigate the impact of adjuvant therapy on the survival of patients with SBA in a meta-analysis. Methods: We performed a comprehensive search of PubMed, EMBASE and the Cochrane Library database between 2010 and 2017. Hazard ratios (HR) with 95% confidence intervals (95%CI) were used to assess the effect of adjuvant chemotherapy and/or radiation treatment after curative surgery in patients with SBA. Moreover, impact of age, sex, stage, differentiation, lymph node involvement, and margin status was also evaluated. Results: We included 15 studies to evaluate the effect of adjuvant therapy on the survival of patients with SBA. The pooled HR of overall survival (OS) involving 5986 patients showed that adjuvant therapy did not have a statistically significant effect on the survival of patients with SBA (pooled HR = 0.89, 95% CI = 0.73–1.09, p = 0.25). Further, 607 patients with duodenal adenocarcinoma (DA) had similar results (pooled HR = 0.96, 95% CI = 0.75–1.23, p = 0.77). Similarly, adjuvant treatment vs. non-adjuvant treatment in terms of disease-free survival (DFS) or relapse-free survival (RFS) showed the same results (pooled HR = 0.89, 95% CI = 0.64–1.23, p = 0.48). However, we found that adjuvant therapy resulted in favorable postoperative survival in Europe according to the subgroup analysis (pooled HR = 0.63, 95% CI = 0.5–0.8, p = 0.0002). In addition, the pooled HR shows that stage, differentiation, lymph node involvement, and margin status were related to the OS of patients with SBA. Conclusion: Patients with SBA who received adjuvant therapy after surgery did not receive a significant survival benefit. Adjuvant therapy may be more useful in advanced cancer or metastatic patients.