Purpose: Surgery is recommended for most patients with gastro-entero-pancreatic neuroendocrine neoplasias (GEP-NENs). Rates of complications and perioperative mortality have been reported in few mostly retrospective single-center series, but there has been no detailed analysis on risk factors for perioperative complications and mortality to date. Methods: Data of patients with GEP-NENs operated between January 2015 and September 2018 were retrieved from EUROCRINE©, a European online endocrine surgical quality registry, and analyzed regarding rate and risk factors of surgical complications. Risk factors were assessed by logistic regression. Results: Some 376 patients (211 female, 167 male; age median 63, range 15–89 years) were included. Most NENs were located in the small intestine (SI) (n = 132) or pancreas (n = 111), the rest in the stomach (n = 34), duodenum (n = 30), appendix (n = 30), colon, and rectum (n = 22), or with unknown primary (n = 15). Of the tumors, 320 (85.1%) were well or moderately differentiated, and 147 (39.1%) of the patients had distant metastases at the time of operation. Severe complications (Dindo-Clavien ≥ 3) occurred in 56 (14.9%) patients, and 4 (1.1%) patients died perioperatively. Severe complications were more frequent in surgery for duodenopancreatic NENs (n = 31; 22.0%) compared with SI-NENs (n = 15; 11.4%) (p = 0.014), in patients with lymph node metastases operated with curative aim of surgery (n = 24; 21.4%) versus non-metastasized tumors or palliative surgery (n = 32; 12.1%) (p = 0.020), and in functioning tumors (n = 20; 23.0%) versus non-functioning tumors (n = 30; 13.5%) (p = 0.042). Complication rates were not significantly associated with tumor stage or grade. Conclusions: Severe complications are frequent in GEP-NEN surgery. Besides duodenopancreatic tumor location, curative resection of nodal metastases and functioning tumors are risk factors for complications.

Background: Some gender-related differences have been reported in multiple endocrine neoplasia type 1 (MEN1), although not all reports are conclusive. This systematic review with analysis of the own MEN1 cohort evaluates gender differences and potential consequences for screening. Methods: A systematic review of the literature between 1990 and 2019 with the search terms “MEN1” or “multiple endocrine neoplasia type 1” and “gender” or “sex” was performed. In addition, the prospectively collected data of a genetically confirmed MEN1 cohort of the Philipps University Marburg were retrospectively analyzed. Results: Review of the literature identified five retrospective case series with original data of 1,057 MEN1 patients. One series suggested a higher frequency of pancreatic neuroendocrine neoplasms (NEN), especially gastrinomas, in men (61 vs. 54%) and a higher frequency of pituitary tumors in women (47 vs. 30%), but others did not. Only thymic NEN occurred predominantly in men throughout all studies. Women with MEN1 were found to have an increased risk of breast cancer. In the own series consisting of 116 MEN1 patients (male = 58, female = 58), thymic lesions were also more frequently detected in male patients (male = 5, female = 1). No gender difference was found with regard to the other manifestations. Conclusion: Regarding the typical MEN1 tumor manifestations, gender-adapted diagnostic and therapeutic approaches cannot be recommended. Female MEN1 patients should be encouraged to participate in breast cancer screening programs.