Outcomes of cytoreductive operations for peritoneal carcinomatosis with or without liver cytoreduction in patients with small bowel neuroendocrine tumors

Background: This study determines how much cytoreduction for small bowel neuroendocrine tumors with peritoneal carcinomatosis and liver metastases can be achieved and the corresponding survival benefits of different levels of clearance. Methods: Records of patients with small bowel neuroendocrine tumors with peritoneal carcinomatosis were reviewed and scored using the Lyon Stage system. Kaplan-Meier survival was calculated and compared by log-rank analysis. Results: Among 323 patients with small bowel neuroendocrine tumors identified, 98 (30%) had peritoneal carcinomatosis. At laparotomy, 82% had Lyon Stage ≥3 compared with 78% who had Lyon Stage ≤2 after debulking (P < .00001). Median overall survival for Lyon Stage = 0 was 132 months and 51 months for Lyon Stage ≥1 (P = .026). For incomplete clearance, overall survival was 76 months for Lyon Stage ≤1 compared with 32 months for Lyon Stage ≥3 (P = .037). Seventy-nine (81%) patients had liver metastases, and 57 underwent >70% liver metastases cytoreduction. Overall survival was 76 months for Lyon Stage ≤1 and >70% liver metastases cytoreduction, 38.5 months for Lyon Stage ≥3 and >70% liver metastases cytoreduction, 22 months for Lyon Stage ≤1 and liver metastases not cytoreduced, and 20 months for Lyon Stage ≥3 and liver metastases not cytoreduced (P = .018). Conclusion: A majority of patients with peritoneal carcinomatosis from small bowel neuroendocrine tumors can be cytoreduced. Best survival times are seen with complete clearance; however, there are improved survival times for Lyon Stage ≤1. In patients with liver metastases, best survival after cytoreduction is seen when both Lyon Stage ≤1 and liver metastases >70% are achieved.