Prognostic factors and survival in endocrine tumor patients: comparison between gastrointestinal and pancreatic localization

Since gastro-entero-pancreatic endocrine tumors are rare and heterogeneous diseases, their prognosis and long-term survival are not well known. This study aimed at identifying prognostic factors and assessing long-term survival in gastro-entero-pancreatic endocrine tumors. A total of 156 patients enrolled. Prognostic factors were determined by univariate/multivariate analysis; survival rates were assessed by the Kaplan-Meier method. The tumors were non-functioning in 59.6% of patients, and originated from the pancreas in 42.9%. At diagnosis, 64.3% of patients had metastases. The tumors were well differentiated in 89.6% of patients. Ki67 was >2% in 39.6% of patients. Primary tumor size was > 3 cm in 49.6% of cases studied. For the univariate analysis, the negative prognostic factors were: pancreatic origin (rate ratio 4.64, P= 0.0002), poorly differentiated tumor (rate ratio 7.70, P= 0.0001), primary tumor size >3 cm (rate ratio 4.26, P= 0.0009), presence of distant metastases (liver: rate ratio 5.88, P=0.01; distant extra-hepatic: rate ratio 13.41, P= 0.0008). The pancreatic site, the poor degree of differentiation and the distant metastases were confirmed as negative prognostic factors at multivariate analysis. Overall 5-year survival rate was 77.5%. Survival rates differed according to: primary tumor site (62% for pancreatic vs 89.9% for gastrointestinal tract, P = 0.0001) and size (65.7% for > 3 cm vs 88.8% for <= 3 cm, P = 0.0003), degree of differentiation (22% for poor vs 86.8% for good, P<0.0001), Ki67 (53.5% for >2% vs 90.1 % for <= 2%, P = 0.003), metastases (96.1, 77, 73.3 and 50.1% for absent, local, liver and distant extra-hepatic metastases respectively), age at diagnosis (85.3% for <= 50 years vs 70.3% for >50 years, P=0.03). Although 64.3% of gastro-entero-pancreatic endocrine tumors present metastases at diagnosis, the 5-year survival rate is 77.5%. Pancreatic site, a poor degree of tumor cell differentiation and distant extra-hepatic metastases are the major negative prognostic factors.