Active Surveillance versus Surgery of Nonfunctioning Pancreatic Neuroendocrine Neoplasms ≤2 cm in MEN1 Patients

BACKGROUND: Aim of this study was to evaluate the efficacy of a conservative treatment for NF-PNEN ≤2 cm in MEN1-affected patients compared with a surgical treatment. METHODS: Databases of 4 tertiary-referral institutions (San Raffaele Scientific Institute, Milan; University of Marburg, Marburg; University of Padua, Padua; The Royal Free Hospital, London) were analyzed. Comparison of conservative management versus surgery at initial diagnosis of NF-PNEN ≤2 cm between 1997 and 2013 was performed. RESULTS: Overall, 27 patients (45%) underwent up-front surgery and 33 patients (55%) were followed-up at initial diagnosis. A higher proportion of patients in the surgery group were female (70 vs. 33%, p = 0.004). Patients were mainly operated in the period 1997-2007 compared with the period 2008-2013 (n = 17, 63 vs. 37%, p = 0.040). The rate of multifocal tumors was higher in the surgical group (n = 24, 89%) compared with no surgery group (n = 22, 67%, p = 0.043). After a median follow-up of 126 months, one patient deceased for postoperative complications within 30 days from surgery. The 5-, 10-, and 15-year the progression free survival (PFS) rates were 63, 39, and 10%, respectively. The median PFS were similar between the two groups. Overall, 13 patients (32.5%) were operated after an initial surgical or conservative treatment. The majority of surgically treated patients had stage 1 (77.5%), T1 (77.5%) and G1 (85%) tumors. CONCLUSIONS: NF-PNEN ≤20 mm in MEN1 patients are indolent neoplasms with a low oncological risk. Surgical treatment of these tumors at initial diagnosis is rarely justified in favor of a conservative treatment.