Long-Term Survival with Long-Acting Somatostatin Analogues Plus Aggressive Cytoreductive Surgery in Patients with Metastatic Neuroendocrine Carcinoma.

Background: Long-acting somatostatin analogues (S-LAR) improve recurrence-free survival in patients with metastatic neuroendocrine tumor (NET) from gastrointestinal (GI) primary, but their impact on overall survival when combined with aggressive cytoreductive surgery is unclear.

Study Design: We reviewed our institutional cancer database to identify patients who underwent cytoreductive surgery for metastatic NET from GI primary between December 1997 and June 2013. Additionally, a cohort selected from 3,384 metastatic neuroendocrine cases in the SEER-Medicare database (January 2003 to December 2009) was used to verify and expand on our results.

Results: Most of the 49 patients from our institution had primary lesions in the small intestine (22 of 49 [44.9%]) or pancreas (14 of 49 [28.6%]); 37 patients (75.5%) had metastatic disease at initial diagnosis. These patients underwent 1 (32 of 49 [65.3%]), 2 (11 of 49 [22.4%]), or at least 3 (6 of 49 [12.3%]) surgical procedures; 33 patients (67.3%) underwent resection plus ablation, 19 (38.7%) underwent major hepatectomy, and 34 (69.4%) received S-LAR (29.4% administered preoperatively). Median follow-up was 112 months. Rates of 1-, 5-, 10-, and 15-year disease-specific survival (DSS) were 94%, 78%, 64%, and 31%, respectively, in the 34 patients undergoing aggressive cytoreductive surgery plus S-LAR. Of the SEER-Medicare population, 1,741 patients met inclusion criteria. The DSS for the 104 patients treated with combination therapy was 68.3% at 5 years and 60.6% at 10 years, as compared with 54.7% and 51.8%, respectively, for the 202 patients receiving surgery alone, and 50.0% and 36.0%, respectively, for the 342 patients receiving S-LAR alone (p < 0.0001). The group receiving neither treatment (n = 1,093) had 5-year and 10-year DSS of 34.3% and 26.3%, respectively.

Conclusions: Long-acting somatostatin analogues combined with aggressive cytoreductive surgery improves the long-term survival of select patients with metastatic NET from GI primary.