Carcinoids: the association of histologic growth pattern and survival.

There are five generally accepted carcinoid histologic growth patterns, i.e., insular, trabecular, glandular, undifferentiated, and mixed. To determine their possible prognostic significance, a panel of pathologists studied the growth patterns of 138 carcinoids collected from an Eastern Cooperative Oncology Group carcinoid advanced stage disease chemotherapy investigation. Survival times were measured from date of initial pathologic diagnosis of carcinoid disease to date of either death or last follow-up. Significant differences were observed in survival times between the five major growth patterns (P less than 0.001). Within the mixed growth pattern group, significant differences in survival time were also observed (P approximately 0.05). In decreasing order of median survival time in years, the growth patterns ranked as follows: mixed insular plus glandular, 4.4; insular, 2.9; trabecular, 2.5; mixed insular plus trabecular, 2.3; three pooled low incidence rate mixed growth patterns, 1.4; glandular, 0.9; and undifferentiated, 0.5. Histologic growth patterns are recommended as a stratification factor in future studies of this disease.