Role of Staging in Patients with Small Intestinal Neuroendocrine Tumours

Small bowel neuroendocrine tumours are the commonest malignancy arising in the small intestine and have substantially increased in incidence in recent decades. Patients with small bowel neuroendocrine tumours commonly develop lymph node and/or distant metastases. Here, we examine the role of staging in 84 surgically treated patients with small bowel neuroendocrine tumours, comparing diagnostic information yielded from morphological, functional and endoscopic modalities. Furthermore, we correlate pre-operative staging with intra-operative findings in a sub-cohort of 20 patients. The vast majority of patients had been histologically confirmed to have low-grade (Ki-67 <2%) disease; however, lymph node and distant metastases were observed in 74 (88.1%) and 51 (60.7%) of patients at presentation, respectively. Liver metastases were evident in 48 (57.1%) patients, with solely peritoneal and bone metastases observed in 2 (2.4%) and 1 (1.2%) patients, respectively. Forty patients (47.6%) received multimodal treatment. In our sub-cohort analysis, pre-operative imaging understaged disease in 14/20 (70%) when compared with intra-operative findings. In patients with multifocal primary tumours and miliary liver metastases, no imaging modality was able to detect entire disease spread. Overall, presently available imaging modalities heavily underestimate disease stage, with meticulous intra-operative abdominal examination being superior to any imaging technology. Multimodal treatment has an important role in prolonging survival.