Surgical Approach in the Treatment of Neuroendocrine Neoplasms

Gastro-entero-pancreatic neuroendocrine neoplasms (GEP)-NENs have had a rising incidence during recent decades, owing to improved detection by multidimensional imaging and endoscopy, and increased awareness of characteristic histological features. A majority of NENs have malignant properties, but often slow and indolent progression, except a minority group with poor differentiation and aggressive behavior. Foregut, including gastric NENs, have variable disease presentation and different, type-specific, requirements of treatment. The most common gastric NENs occur secondary to chronic atrophic gastritis (CAG), with considerably more benign features than non-CAG-related gastric NENs. Metastatic midgut, small intestinal NENs (Si-NENs) have been over-represented at referral centers since they cause the carcinoid syndrome, which has required more complex combined oncologic and surgical treatment. The Si-NENs have early spread to locoregional lymph nodes in the root of the mesentery and the liver, but may with appropriate surgery and somatostatin analog treatment reach long survival. Hindgut/colo-rectal NENs are not associated with the carcinoid syndrome, the vast majority presents as incidentally discovered small polyps, which can be safely removed by endoscopy, whereas larger and deeper invasive lesions are malignant and require extensive surgery combined with other treatment. Surgery is the only potentially curative therapy for localized NENs, but may often be crucially important also for patients with advanced disease. Appropriate surgery can be a necessary prerequisite for other treatment options and improve treatment results. A multidisciplinary approach, with involvement of oncologists, surgeons, radiologists, and pathologists, has proved important for the recent progress in the management of NENs.