Novel Prognostic Factors in Resected Small Bowel Adenocarcinoma

Small bowel adenocarcinoma is a rare malignancy with variable survival depending on multiple factors. Increased age, increased tumor stage, and low lymphocyte-to-monocyte ratio before surgery are associated with poor overall survival. Patients with stage III disease showed improved survival when provided adjuvant chemotherapy. Background: Small bowel adenocarcinoma (SBA) is a rare malignancy affecting approximately 3000 patients per year in the United States, and there is limited evidence prognosticating patients with resected SBA. We aimed to evaluate prognostic factors and the role of adjuvant therapy in patients with resected SBA. Patients and Methods: Two hundred forty-one patients who had resected stage I-III SBA were retrospectively identified at a single tertiary referral institution. Overall survival (OS) analysis was performed by the Kaplan-Meier method, and Wilcoxon tests were used for statistical comparisons. Cox proportional hazards were performed to identify significant variables by univariate and multivariate analysis. Results: Median OS for the entire group was 54.5 months (95% confidence interval [CI], 37.2-81.2 months), with 5- and 10-year OS of 48% and 35%. Median follow-up was 113.7 months (95% CI, 97.9-126.6 months). For patients with stage III disease who received adjuvant therapy, the median OS was 33.8 months (95% CI, 27.8-78.8) compared to 24.7 months (95% CI, 11.5-37.8) for patients with no adjuvant therapy (P < .01). Male sex, advanced T stage, advanced N stage, increased positive lymph node ratio, lymphocyte-to-monocyte ratio < 1.56, presence of residual disease, and earlier date of diagnosis predicted worse survival on univariate analysis. Age > 60 years, lymphocyte-to-monocyte ratio < 1.56, and advanced T stage were identified as independent negative predictors of OS for all patients by multivariate analysis. Conclusion: Advanced age, advanced T stage, and lymphocyte-to-monocyte ratio < 1.56 independently predicted survival in resected SBA. Adjuvant therapy is associated with improved survival in patients with resected stage III SBA. (C) 2019 Elsevier Inc. All rights reserved.