Implications of Incidentally Discovered, Nonfunctioning Pancreatic Endocrine Tumors

Abstract

Objectives To describe the characteristics and outcomes after resection of incidentally discovered, nonfunctioning pancreatic endocrine tumors (PETs). Design Case series. Setting Academic hospital. Patients Consecutive patients with an incidentally identified, nonfunctioning PET resected from May 1, 1977, through July 31, 2009. Main Outcome Measures Operative morbidity and survival after resection. Results A total of 139 patients with median age of 56 years (range, 21–85 years) underwent resection; tumor size ranged from 0.4 to 17.0 cm, with median size of 3.0 cm. No perioperative deaths were reported. Sixty-one patients (43.9%) experienced a perioperative complication. Twenty-six tumors (18.7%) were classified as benign, 39 (28.1%) as malignant, and 72 (51.8%) as uncertain. We were unable to confidently classify 2 tumors due to lack of information regarding mitotic rate in the pathology report. Complete follow-up was available for 112 patients (80.6%) (median, 34.2 months). Five-year actuarial survival rates were 88.8% for patients with benign disease, 92.5% for patients with tumors of uncertain biology, and 49.8% for those with malignant tumors (P=.01). Late metastasis, tumor recurrence, or disease progression were seen in 1 patient (3.8%) with tumors initially classified as benign, 8 patients (11.1%) with uncertain tumors, and 15 patients (38.5%) with tumors classified as malignant (P<.001). Of the 39 patients with tumors 2 cm or smaller, 3 (7.7%) had late metastases or recurrence. When compared with patients with symptomatic, nonfunctioning PETs, no large difference was observed in tumor size, patient age, disease, or survival. Conclusions Incidentally detected, nonfunctioning PETs can display aggressive behavior, even when small. Although patients with malignant disease had diminished survival and increased rates of recurrence, benign histologic findings did not eliminate the possibility of progression. Patients with incidentally discovered, nonfunctioning PETs should undergo tumor resection and careful postoperative surveillance, even if surgical pathologic findings suggest benign disease.

Original paper Morphological and immunohistochemical profile of pancreatic neuroendocrine neoplasms

“…In our study, there was a significant association between pT, tumour grade 2004 (p = 0.005) and vascular invasion (p = 0.005), explaining the association between pT and prognosis through common mechanisms of anaplasia and invasive tumour properties. pN1 was found in 20.0% of PNEN, in accordance with other observations [41,[45][46][47]50] and was strongly predicted by older age. Age exceeding 60 years has been shown to be associated with lower survival, even in patients with low-grade (G1) gastroenteropancreatic PNENs [51].…”

“…Within the study, PNEN size ranged from 1.2-12.5 cm, in accordance with the published results [41,[45][46][47]. Prognostic value has been attributed to the size of PNEN.…”

“…In PNENs, R0 can be reached in 68-87.1% of patients [47,53]. R0 PNENs still recur in 23.1% of patients, leading to death in 11.1% [46].…”

Neutrophil-lymphocyte ratio predicts survival in pancreatic neuroendocrine tumors

“…PNETs are highly heterogeneous neoplasms presenting a spectrum of biologic behavior (7,8). Aggressive progression can even be observed in incidentally detected and small tumors (9). Potential prognostic factors, including mitoses, vascular invasion, metastasis, necrosis, Ki-67 expression, and nuclear grade, are mostly based on pathological examination (2,3,10,11).…”

Behavior of small, asymptomatic, nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs)

“…Other authors suggest that surgery is indicated in any case because NF-PNETs should always be considered as potentially malignant tumors, and a proper histological examination of the tumor (including the mitotic and Ki-67 indexes) is possible only on the resected specimen. 21,22 Previous studies have reported that several factors are associated with survival, including age, 23,24 tumor size, 9,23,[25][26][27] grade/differentiation, 14,24,25,28 LN status, 25,29 presence of distant metastases, 14,23,24,29 and surgical resection. 14,23 Age has consistently been found to be a powerful predictor of survival in patients undergoing resection of PNETs.…”