The management of non-functional pancreatic neuroendocrine tumors (NF-PNETs) less than 2 cm in size is controversial, and there is no clear consensus on whether or not these tumors should be removed.
Some studies have suggested that small NF-PNETs have a very low risk of progression or metastasis and may not require immediate surgical intervention. Instead, they may be monitored with regular imaging studies to detect any changes in size or appearance.
Other studies have suggested that even small NF-PNETs have a risk of progression or metastasis, and therefore, surgical removal should be considered.
The decision to remove a small NF-PNET should be made on a case-by-case basis, taking into account factors such as the patient’s age, overall health, and risk of surgical complications, as well as the size, location, and characteristics of the tumor. A multidisciplinary team of healthcare professionals, including surgeons, endocrinologists, and radiologists, should be involved in the decision-making process.
In the United States, the National Comprehensive Cancer Network (NCCN) provides guidelines for the management of pancreatic neuroendocrine tumors (PNETs), including recommendations for surgical management.
According to the NCCN guidelines, surgical removal is the primary treatment for PNETs. The goal of surgery is to remove the tumor with negative margins (i.e., no tumor cells remaining at the edges of the removed tissue) and to avoid damage to surrounding structures whenever possible. The extent of surgery depends on the size and location of the tumor, as well as whether the tumor is functional (i.e., producing hormones) or non-functional.
For small (<2 cm) non-functional tumors located in the body or tail of the pancreas, a minimally invasive (e.g. robotic) or open distal pancreatectomy with or without splenectomy is recommended. For larger tumors, a distal pancreatectomy with or without splenectomy, or a central pancreatectomy, may be necessary.
For small (<2 cm) functional tumors located in the body or tail of the pancreas, an enucleation (i.e., removal of the tumor while preserving pancreatic tissue) may be considered. For larger functional tumors, a distal or central pancreatectomy may be necessary.
For tumors located in the head of the pancreas, a pancreaticoduodenectomy (i.e., Whipple procedure) is typically performed.
The NCCN guidelines also recommend that surgery should be performed by experienced surgeons in specialized centers with expertise in managing PNETs.
European Society for Medical Oncology (ESMO) guidelines and the National Comprehensive Cancer Network (NCCN) guidelines for pancreatic neuroendocrine tumors (PNETs):
ESMO Clinical Practice Guidelines for Neuroendocrine Neoplasms 2018: https://www.esmo.org/content/download/211641/3802794/file/ENETS-Guidelines-for-NETs-2018-All-chapters.pdf
NCCN Clinical Practice Guidelines in Oncology: Neuroendocrine and Adrenal Tumors, Version 2.2021: https://www.nccn.org/professionals/physician_gls/pdf/neuroendocrine.pdf
Please note that these guidelines are regularly updated, so it is important to check for the most current version.