Survival for small, well-differentiated PNETs in relation to treatment

• Published in: Journal of clinical oncology Vol. 36; no. 4_suppl; p. 222
• Main Authors: Julian, bao-Quynh, Ituarte, Philip HG, Jutric, Zeljka, Singh, Gagandeep, Paz, Isaac Benjamin, Lewis, Aaron G
• Format: Journal Article
• Language: English
• Published: 01.02.2018
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.2018.36.4_suppl.222

Abstract only 222 Background: Management of small well-differentiated pancreatic neuroendocrine tumors (PNETs) is controversial, and the malignant potential remains uncertain. Treatment options include observation (OB), enucleation (ENUC), and formal resection (Distal pancreatectomy – DP, Whipple/Total pancreatectomy – PD). Our objective was to analyze the association between treatment types of small PNETs and overall survival (OS). Methods: The California Cancer Registry linked with the Office of Statewide Health Planning and Development inpatient database was queried from 2000-2012 for patients with < 3 cm, nonfunctional, stage I–II PNETs. Exclusion: poorly-differentiated PNETs or metastases within 6 months. Non-parametric statistics (Kruskal-Wallis) or Fisher’s exact test were used to determine if any patient characteristics were associated with type of treatment (surgery or observation). Ten-year OS was estimated by the Kaplan-Meier method. A multivariate model was performed using Cox proportional hazards. Results: Of 1,862 patients with PNETs, 204 were small, well-differentiated. Treatments include: OB n = 41, EN n = 20, DP n = 106, or PD n = 67. Few patients developed distant recurrences past 6 months (OB, n = 0; EN, n = 0; DP, n = 2; PD, n = 1). On bivariate analysis, comorbidities (2 or more, p = 0.024), insurance type (p = 0.018), and mean number of lymph nodes retrieved (EN = 1.8 +/- 4.1; DP = 6.3 +/- 7.63; PD = 11.0 +/-8.5) were associated with treatment. Patient gender, race, socio-economic status, hospital type, tumor size, grade (well vs. moderate), and lymph node status at diagnosis were not associated with treatment type. On multivariate analysis, treatment type was not associated with worse OS (p = 0.098). Ten-year OS was similar between treatment groups (OB = 92%, EN = 100%, DP = 95%, PD = 95%, p= 0.1828). Conclusions: In this unique study accounting for time of metastasis in patients who present with early stage, well-differentiated PNETs, observation, enucleation, and resection are equally associated with long-term survival. In the appropriately selected patient group, enucleation or observation may be alternatives to more aggressive surgery.