Neuroendocrine tumors of the pancreas: Degree of cystic component predicts prognosis

• Published in: Surgery Vol. 160; no. 3; pp. 708 - 713
• Main Authors: Cloyd, Jordan M., MD, Kopecky, Kimberly E., MD, Norton, Jeffrey A., MD, Kunz, Pamela L., MD, Fisher, George A., MD, Visser, Brendan C., MD, Dua, Monica M., MD, Park, Walter G., MD, MS, Poultsides, George A., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2016
• Subjects: Adult; Aged; Female; Humans; Male; Middle Aged; Neoplasm Grading; Neoplasm Invasiveness; Neuroendocrine Tumors - mortality; Neuroendocrine Tumors - pathology; Neuroendocrine Tumors - surgery; Pancreatectomy; Pancreatic Neoplasms - mortality; Pancreatic Neoplasms - pathology; Pancreatic Neoplasms - surgery; Retrospective Studies; Surgery; Survival Rate; Treatment Outcome
• ISSN: 0039-6060; 1532-7361
• DOI: 10.1016/j.surg.2016.04.005

Background Although most pancreatic neuroendocrine tumors are solid, approximately 10% are cystic. Some studies have suggested that cystic pancreatic neuroendocrine tumors are associated with a more favorable prognosis. Methods A retrospective review of all patients with pancreatic neuroendocrine tumors who underwent operative resection between 1999 and 2014 at a single academic medical center was performed. Based on cross-sectional imaging performed before operation, pancreatic neuroendocrine tumors were classified according to the size of the cystic component relative to the total tumor size: purely cystic (100%), mostly cystic (≥50%), mostly solid (<50%), and purely solid (0%). Clinicopathologic characteristics and recurrence-free survival were assessed between groups. Results In the study, 214 patients met inclusion criteria: 8 with purely cystic tumors, 7 with mostly cystic tumors, 15 with mostly solid tumors, and 184 with purely solid tumors. The groups differed in terms of tumor size (1.5 ± 0.5, 3.0 ± 1.7, 3.7 ± 2.6, and 4.0 ± 3.5 cm), lymph node positivity (0%, 0%, 26.7%, and 34.2%), intermediate or high grade (0%, 16.7%, 20.0%, and 31.0%), synchronous liver metastases (0%, 14.3%, 20.0%, and 26.6%) and need for pancreaticoduodenectomy (0%, 0%, 6.7%, and 25.0%), respectively. No cases of purely cystic pancreatic neuroendocrine tumors were associated with synchronous liver or lymph node metastasis, intermediate/high grade, recurrence, or death due to disease. Among patients presenting without metastatic disease, 10-year recurrence-free survival was 100% in patients with purely and mostly cystic tumors versus 53.0% in patients with purely and mostly solid tumors; however, this difference did not reach statistical significance. Conclusion Pancreatic neuroendocrine tumors demonstrate a spectrum of biologic behavior with an increasing cystic component being associated with more favorable clinicopathologic features and prognosis. Purely cystic pancreatic neuroendocrine tumors may represent 1 subset that can be safely observed without immediate resection.