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

BACKGROUND: The aim of this study was to evaluate the efficacy of conservative treatment for nonfunctioning pancreatic neuroendocrine neoplasms (NF-PNEN) ≤2 cm in multiple endocrine neoplasia type 1 (MEN1)-affected patients compared with surgical treatment.

METHODS: The databases of 4 tertiary referral institutions (San Raffaele Scientific Institute, Milan; Philipps-Universität Marburg, Marburg; University of Padua, Padua; Royal Free Hospital, London) were analyzed. A comparison of conservative management and 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 after the initial diagnosis. A higher proportion of patients in the surgery group were female (70 vs. 33%, p = 0.004). Patients were mainly operated on in the period 1997-2007 as compared with the period 2008-2013 (n = 17; 63 vs. 37%; p = 0.040). The rate of multifocal tumors was higher in the surgery group (n = 24; 89%) than in the 'no surgery' group (n = 22; 67%; p = 0.043). After a median follow-up of 126 months, 1 patient deceased due to postoperative complications within 30 days after surgery. The 5-, 10-, and 15-year progression-free survival (PFS) rates were 63, 39, and 10%, respectively. The median PFS was similar in the two groups. Overall, 13 patients (32.5%) were operated on after initial surgical or conservative treatment. The majority of the surgically treated patients had stage 1 (77.5%), T1 (77.5%), and G1 (85%) tumors.

CONCLUSIONS: NF-PNEN ≤2 cm in MEN1 patients are indolent neoplasms posing a low oncological risk. Surgical treatment of these tumors at initial diagnosis is rarely justified in favor of conservative treatment.