Characteristics of Study Population (n = 112)
| Characteristic | n |
| Sex | |
| Male | 63 (56%) |
| Female | 49 (44%) |
| Mean age (y) | 62 (range, 30–84) |
| Site of primary tumor | |
| Lung carcinoid | 9 (8%) |
| NET of unknown primary site origin | 23 (21%) |
| Gastric NET | 1 (1%) |
| Small intestinal NET | 49 (44%) |
| Pancreatic NET | 19 (17%) |
| NET originated from cecum/appendix | 6 (5%) |
| NET originated from the rectum | 2 (1.5%) |
| NET originated from extrahepatic biliary tract | 2 (1.5%) |
| NET originated from the esophagus | 1 (1%) |
| Functional status | |
| Nonfunctioning | 72 (64%) |
| Functioning | 40 (36%) |
| Carcinoid syndrome | 35 (31%) |
| Gastrinoma | 4 (3.6%) |
| Glucagonoma | 1 (0.9%) |
| Grade (World Health Organization)* | |
| Low-grade (G1) Ki-67, ≤2% | 31 (28%) |
| Intermediate-grade (G2) Ki-67, 3%–20% | 70 (62%) |
| High-grade (G3) Ki-67, >20% | 9 (8%) |
| Ki-67 index not available | 2 (2%) |
| Primary removed? | |
| Yes | 52 (46%) |
| No | 60 (54%) |
| Previous treatment | |
| Somatostatin analogs | 35 (31%) |
| Surgery | 56 (50%) |
| Chemotherapy | 40 (36%) |
| Interferon α | 47 (42%) |
| Radio frequency ablation (liver metastases) | 7 (6%) |
| External radiation therapy | 2 (2%) |
| Hepatic artery chemoembolization | 7 (6%) |
| Peptide receptor radionuclide therapy | 18 (16%) |
↵* Lung carcinoids all had mitotic counts ≤ 10 and were accordingly placed in G1 or G2 groups.