Malignant pancreatic neuroendocrine tumour: Lymph node ratio and Ki67 are predictors of recurrence after curative resections

Introduction: Malignant pancreatic neuroendocrine tumours (PNENs) are generally associated with a good prognosis after radical resection. In other pancreatic malignancies predictors of recurrence and the role of lymph node ratio (LNR) are well known, but both have been scarcely investigated for malignant PNETs. Methods: The prospective database from the surgical Department of Verona University was queried. Clinical and pathological data of all patients with resected malignant PNET between 1990 and 2008 were reviewed. Univariate and multivariate analysis were performed. Results: Fifty-seven patients (male/female ratio = 1) with a median age of 58 years (33-78) entered in the study. Twenty-nine (51%) patients underwent pancreaticoduodenectomy and 28 (49%) distal pancreatectomy. Postoperative mortality was nil with a 37% morbidity rate. There were 36 (63%) patients with lymph node metastases (N1). Of these, 23 (64%) had a lymph node ratio (LNR) >0 and ≤0.20 and 13 (36%) had a LNR >0.20. The median overall survival and the median disease free survival (DFS) were 190 and 80 months, respectively. Recurrent disease was identified in 24 patients (42%) with a 2 and 5-year DFS rate of 82% and 49%, respectively. On multivariate analysis, LNR >0.20 (HR = 2.75) and a value of Ki67 >5% (HR = 3.39) were significant predictors of recurrence (P <0.02). Conclusions: After resection for malignant PNETs, LNR and a Ki67 >5% are the most powerful predictors of recurrence. The presence of these factors should be considered for addressing patients to adjuvant treatment in future clinical trials.