Association between surveillance imaging and survival outcomes in small bowel neuroendocrine tumors

Abstract

Background Surveillance guidelines following the resection of small bowel neuroendocrine tumors (SB‐NETs) are inconsistent. We evaluated the impact of surveillance imaging on SB‐NET recurrence and overall survival (OS). Methods Patients with completely resected SB‐NETs referred to a provincial cancer center (2004–2015) were reviewed. Associations between imaging frequency, recurrence, post‐recurrence treatment, and OS were determined using univariate and Cox‐regression analyses. Results Among 195 completely resected SB‐NET patients, 31% were ≥70 years, 43% were female, and 80% had grade 1 disease. Imaging frequency was predictive of recurrence (hazard ratio 2.52, 95% confidence interval 1.84–3.46, p < 0.001). 72% underwent interventions for recurrent disease. Patients who were treated for the recurrent disease had comparable OS to those who did not recur (median 152 vs. 164 months; p = 0.25). Imaging frequency was not associated with OS in those with treated recurrent disease (p = 0.65). Patients who recurred underwent more computerized tomography (CT) scans than those who did not recur (CT: 1.47 ± 0.89 vs. 1.02 ± 0.81 scans/year, p < 0.001). Detection of disease recurrence was 5%–7% per year during the first 6 years of surveillance and peaked at 17% in Year 9. Conclusion Less frequent imaging over a longer duration should be emphasized to capture clinically relevant recurrences that can be treated to improve OS.