Prognostic Factors Associated with Outcomes in Small Bowel Neuroendocrine Tumors

Small bowel neuroendocrine tumors (SBNET) account for most gastrointestinal neuroendocrine tumors. Patients often present with late-stage disease; however, there is little information regarding factors that contribute to recurrence. Database review identified 301 patients diagnosed with SBNET between 1990 and 2013. Univariate analysis included patients who underwent complete resection. Survival was estimated by the Kaplan-Meier method. A total of 147 patients met study criteria. Average age was 60 years (range 21-91); 49 per cent were male. Thirty-seven (25.3%) patients had laparoscopic resection, and 29 (19.9%) patients had only small bowel disease, whereas 108 (72.6%) had nodal metastasis. Five-year overall and disease-free survival were 97.5 and 73.5 per cent. Forty-seven (32%) patients had recurrence. The recurrence group was more likely to have an open operation (59.6 vs 32%, P < 0.01), mesenteric invasion, or lymphatic metastasis (87.2 vs 67%, P < 0.01) compared with the no-recurrence group. Cox regression analysis showed that variables associated with recurrence included nodal disease (HR 9.06, P = 0.03), lymphovascular invasion (LVI) (3.95, P < 0.01), perineural invasion (PNI) (3.48, P < 0.01), and mesenteric involvement (3.77, P = 0.03). Patients with SBNET presenting with nodal metastasis, mesenteric involvement, LVI, or PNI have a higher risk of recurrence. Closer surveillance should be considered after operative resection.