Upfront Small Bowel Resection for Small Bowel Neuroendocrine Tumors With Synchronous Metastases: A Propensity-score Matched Comparative Population-based Analysis

Abstract

Objective: We examined the impact of upfront small bowel resection (USBR) for metastatic small bowel neuroendocrine (SB-NET) compared to nonoperative management (NOM) on long-term healthcare utilization and survival outcomes.

Summary of background data: The role of early resection of the primary tumor in metastatic SB-NET remains controversial. Conflicting data exist regarding its clinical and survival benefits.

Methods: This is a population-based retrospective matched comparative cohort study of adults diagnosed with synchronous metastatic SB-NET between 2001 and 2017 in Ontario. USBR was defined as resection within 6 months of diagnosis. Primary outcomes were subsequent unplanned acute care admissions and small bowel-related surgery. Secondary outcome was overall survival. USBR and NOM patients were matched 2:1 using a propensity-score. We used time-to-event analyses with cumulative incidencefunctions and univariate Andersen-Gill regression for primary outcomes. E value methods assessed the potential for residual confounding.

Results: Of 1000 patients identified, 785 had USBR. The matched cohort included 348 patients with USBR and 174 with NOM. Patients with USBR had lower 3-year risk of subsequent admissions (72.6% vs 86.4%, P < 0.001) than those with NOM, with hazard ratio 0.72 (95% confidence interval 0.570.91). USBR was associated with lower risk of subsequent small bowel-related surgery (15.4% vs 40.3%, P < 0.001), with hazard ratio 0.44 (95% confidence interval 0.29-0.67). E -values indicated it was unlikely that the observed risk estimates could be explained by an unmeasured confounder. Sensitivity analysis excluding emergent resections to define USBR did not alter the results.

Conclusions: USBR for SB-NETs in the presence of metastatic disease was associated with better patient-oriented outcomes of decreased subsequent admissions and interventions, compared to NOM. USBR should be considered for metastatic SB-NETs.