Small intestinal neuroendocrine tumors: prognostic factors and survival

Small intestinal neuroendocrine tumors (SI-NETs) make up 38% of gastroenteropancreatic neuroendocrine tumors. We report our experience with SI-NETs at the National Center for Neuroendocrine Tumors in Norway, focusing on prognostic factors and survival.

The medical records of 258 patients with SI-NETs diagnosed between 1983 and 2007 were retrospectively reviewed. Demographic, clinical and tumor characteristics were registered in a database.

Median age at diagnosis was 62 years (range 28-84); 53% of patients were men. Median survival was 9.3 years [95% confidence interval (CI) 7.6; 10.8]. Survival did not improve for patients diagnosed between 1998 and 2007 compared with those diagnosed between 1990 and 1997 (p=0.44), median survival 8.1 [7.1;9.1] versus 6.8 [4.0; 9.5] years. Overall 5-year survival was 72%, while expected 5-year survival in the general population was 92%. The corresponding relative 5-year survival for the patient group was 78%. Distant metastases, urinary 5-hydroxyindoleacetic acid ratio > or =3.7 times the upper limit of normal, chromogranin A ratio > or =6.2 times the upper limit of normal, age > or =64, male gender, carcinoid heart disease, and Ki-67 > or =5% were associated with decreased survival. Using multivariate analysis, only distant metastases (hazard ratio (HR) 1.98 [1.04;3.76], p=0.04), chromogranin A ratio > or =6.2 (HR 1.90 [1.12; 3.20], p=0.02), and age > or =64 (3.12 [1.93; 5.04], p<0.001) remained independent predictors.

Survival did not improve over the study period. Overall and relative 5-year survival compared favorably with that in population-based studies. Distant metastases, elevated chromogranin A levels, and advanced age were the only independent predictors of poor survival.