Non-functioning pancreatic neuroendocrine tumors: Surgery or observation?

Abstract

Incidentally detected, sporadic, nonfunctional pancreatic neuroendocrine tumors are increasingly diagnosed on imaging studies performed for unrelated purposes. Although their resection is usually recommended, controversy still exists regarding their optimal management, due to their highly variable and difficult to predict biologic behavior. Recently, several studies and guidelines advocated an expectant management approach in small size, low grade, incidentally diagnosed nonfunctional pancreatic neuroendocrine tumors. The aim of this study is to review and summarize the available literature addressing nonfunctional pancreatic neuroendocrine tumors, with an emphasis on surgical management controversies.

A Nationwide Population‐Based Study on the Survival of Patients with Pancreatic Neuroendocrine Tumors in The Netherlands

“…Still, issues of selection bias, small sample and missing data limit our ability to make valid conclusions. Similar studies support or contradict our findings, indicating comparable study bias and the need for prospective data [ 14 – 16 ]. It is imaginable that the reason to refrain from surgery might influence the outcome in both directions.…”

Insights of Outcome after Resection of Small Nonfunctioning Neuroendocrine Pancreatic Tumors

“…We believe that the risks and benefits of operating on such tumors must be weighed, and the prognostic factors for each tumor should be better established. Thus, it would be possible to make better informed decisions regarding management, but there are no well-defined prognostic factors for this purpose yet [ 24 ]. Some centers use specific measures for this decision, such as tumor size (cutoff 2 cm), tumor grade, staging, and the patient's desire [ 24 ].…”

“…Thus, it would be possible to make better informed decisions regarding management, but there are no well-defined prognostic factors for this purpose yet [ 24 ]. Some centers use specific measures for this decision, such as tumor size (cutoff 2 cm), tumor grade, staging, and the patient's desire [ 24 ]. Others say that patients with comorbidities should receive conservative treatment [ 25 ].…”

A comprehensive validation of the novel 8th edition of American Joint Committee on Cancer staging manual for the long-term survivals of patients with non-functional pancreatic neuroendocrine neoplasms

“…[ 9 , 23 ] Patients with NF-p-NENs could benefit from radical resections, depending on tumor size and location within the pancreas. [ 7 – 9 , 25 , 26 ] But recent studies have focused on the controversy for small NF-p-NENs, for many favor 2 cm as the cutoff size to surgery or observation with the considerations of clinical symptoms on admission and tumor grade mainly acquired by ultrasound guided fine needle aspiration. [ 7 , 9 , 25 ]…”

“…[ 4 , 5 ] NF-PNENs may not produce hormones or peptides, produce them at low levels and without hormone-related symptoms, or secrete peptides that cause no symptoms. [ 6 , 7 ] As the most common subgroup of p-NENs, NF-p-NENs mostly occurred in the 4th or 5th decade of life and generally diagnosed at more advanced stages on admission, because of their relatively indolent nature and slow growth causing a delay in onset of symptoms, such as abdominal pain, abdominal mass, weight loss, jaundice, and others. [ 8 , 9 ] There is an increasing number of incidental diagnoses of NF-p-NENs, with the widespread use of high-quality imaging techniques.…”