Small pancreatic neuroendocrine tumors

Rationale: pancreatic neuroendocrine tumors (pNET) are more often diagnosed incidentally due to the use of better imaging techniques. Surgical resection is the only curative treatment and long term follow-up indicates a survival benefit for patients who underwent primary resection. However, pancreatic resections are associated with serious postoperative morbidity. In addition, recent literature shows that incidentally found pNET have a significant smaller size and are more commonly associated with lower tumor stages. Progression or tumor growth in small incidentally found non-functioning pNET seems minimal. Therefore, the European Neuroendocrine Tumor Society (ENETS) has updated their guidelines; surveillance is now recommended for patients with non-functional pNET <2cm. Although this approach seems safe, long term follow-up data are needed to guarantee the safety of this policy.

Objective: To monitor long term effects of a non-operative management of small pNETs.

Study design: A prospective, multicentre, cohort in collaboration with all Dutch Pancreatic Cancer Group (DPCG) affiliated centers that treat patients with pNET.

Study population: patients diagnosed with a pNET <2cm.

Endpoints: Tumor progression and survival will be the primary outcomes. In addition, patients who do undergo a resection despite the guideline will be observed. The reasons to deviate from the initial therapy will be investigated. A secondary outcome will be the quality of life of all patients that are diagnosed with a pNET <2cm, regardless of received therapy.

A conservative approach, rather than surgical resection, is safe for non-functioning grade 1 and 2 pancreatic neuroendocrine tumors <2cm.

Wait-and-see protocol

- year 1: 3, 6, 9, 12 months

- year 2: 18, 24 months

- year 3: 30 36 months

- year 3-10: every 12 months



After surgical resection:

- year 1: 6 and 12 months

- year 2-5: every 12 months

No interventions, since patients will be treated according to the international 2016 ENETS guidelines.