Outcome after resection and radiofrequency ablation of liver metastases from small intestinal neuroendocrine tumours

Background: In patients with small intestinal neuroendocrine tumour (SI-NET), liver resection or radiofrequency ablation (RFA) of liver metastases is performed for palliation of carcinoid syndrome, and in an effort to improve survival. Data are generally reported from case series, and no randomized trials have studied these treatments. The aim was to compare outcome after liver resection and/or RFA with that of non-surgical treatment in patients with liver metastases from SI-NET. Methods: The study included patients with liver metastases from SI-NET who underwent liver RFA/resection or were treated non-surgically. A propensity score match was performed to reduce bias between groups, using baseline variables such as the Charlson co-morbidity index, age, symptoms, carcinoid heart disease, extent of metastases and proliferation index. Results: Some 103 patients who had RFA and/or liver resection were compared with 273 controls. Propensity score matching resulted in two matched groups, each of 72 patients, with no significant differences in baseline variables. The matched resection/RFA and control groups showed no difference in overall survival (both 74 per cent at 5 years; P = 0.869) or disease-specific survival (74 versus 78 per cent respectively at 5 years; P = 1.000). However, urinary 5-hydroxyindoleacetic acid levels were lower (median 77 versus 120 mu mol per 24 h; P = 0.005) and the proportion of patients with progressive disease within the liver was smaller (2 of 18 versus 8 of 18; P < 0.001) in the resection/RFA group after 5 years. Conclusion: These data do not support the use of liver resection and/or RFA in an effort to prolong survival in patients with liver metastases from SI-NET.