Evolving patterns in the detection and outcomes of pancreatic neuroendocrine neoplasms: the Massachusetts General Hospital experience from 1977 to 2005.

OBJECTIVE To assess changing patterns in the detection and outcomes of pancreatic neuroendocrine neoplasms (PNENs). DESIGN Retrospective review from May 21, 1977, through September 16, 2005. SETTING Massachusetts General Hospital, a tertiary care center. PATIENTS We evaluated 168 patients (51% male; mean age, 56 years) who underwent surgery for histologically confirmed PNENs. MAIN OUTCOME MEASURES Surgical outcomes, survival, and changes in presentation of PNENs in 2 time groups: 1977-1999 (77 patients) and 2000-2005 (91 patients). RESULTS Ninety-eight patients (58.3%) had nonfunctioning PNENs, 86 of which were incidental. Insulinomas were the most common type of functional neoplasm (33.3%), followed by gastrinomas and glucagonomas; 12 patients (7.1%) had multiple endocrine neoplasia type 1. Of the neoplasms, 107 (63.7%) were located in the pancreatic body or tail. A pancreaticoduodenectomy was performed in 37 patients (22.0%), distal pancreatectomy was done in 88 (52.4%), and the rest had either middle segment pancreatectomy or enucleation. There were no operative deaths. We classified 76.8% of neoplasms as benign; of those classified as malignant, 25.6% had liver metastases. Of the patients, 10.1% received adjuvant therapy. Complete follow up was available in 90.5% of patients (mean, 63.3 months). Five- and 10-year actuarial survival rates were 77% and 62%, respectively. Incidentally discovered nonfunctioning neoplasms were significantly more frequent in the last 5 years (60.4% vs 40.3%; P = .007), with a trend toward smaller neoplasms (mean, 4.2 cm vs 5.6 cm; P = .19) and lesser likelihood of malignancy (21.8% vs 40.0%; P = .08). CONCLUSIONS We report a large single-center experience with PNENs. Increasing numbers of PNENs are being resected, largely owing to the incidental detection of nonfunctioning neoplasms. This may lead to the treatment of smaller and less malignant neoplasms.