Comparison of tumor markers for predicting outcomes after resection of nonfunctioning pancreatic neuroendocrine tumors

BackgroundThis study compares the predictability of 5 tumor markers for distant metastasis and mortality in pancreatic neuroendocrine tumors (PNETs).MethodsA total of 128 patients who underwent pancreatectomy for nonfunctioning PNETs between 1998 and 2011 were evaluated. Tumor specimens were stained via immunochemistry for cytoplasmic and nuclear survivin, cytokeratin 19 (CK19), c-KIT, and Ki67. Univariate and multivariate regression analyses and receiver operating characteristics curve were used to evaluate the predictive value of these markers.ResultsA total of 116 tumors (91%) were positive for cytoplasmic survivin, 95 (74%) for nuclear survivin, 85 (66.4%) for CK19, 3 for c-KIT, and 41 (32%) for Ki67 >3%. Twelve (9%) tumors expressed none of the markers. Survivin, CK19, and c-KIT had no substantial effect on distant metastasis or mortality. Age >55 years, grade 3 histology, distant metastasis, and Ki67 >3% were associated with mortality (P < .05). A cut-off of Ki67 >3% was the best predictor (83%) of mortality with an area under the curve of 0.85. Ki67 >3% also predicted occurrence of distant metastases with odds ratio of 9.22 and 95% confidence interval of 1.55–54.55 (P < .015).ConclusionOf the 5 markers studied, only Ki67 >3% was greatly associated with distant metastasis and death. Survivin, CK19, and c-KIT had no prognostic value in nonfunctioning PNETs.