Tumor growth rate and prognosis of breast cancer mainly detected by mass screening.

To investigate the relationship between the tumor growth rate of the primary breast cancer and its prognosis, records for 122 breast cancer patients in 9 hospitals in Japan were retrospectively reviewed. These records contained at least two measurements of the same tumor mass in the breast. So the growth rate was estimated from these measurements taken at different points in time. The doubling time of the breast tumors showed an approximately log-normal distribution. The geometric mean of doubling times for all cases was 174 days. The solid-tubular histologic type of carcinoma had the shortest geometric mean of doubling time (126 days), the scirrhous carcinoma had the second shortest one (205 days), and the papillotubular carcinoma had the longest one (252 days). The patients with shorter doubling time of tumor tended to have a poorer prognosis. The Cox multiple regression analysis showed that the tumor growth rate was related significantly with survival, after adjusting for other covariates such as clinical stage, lymph node metastasis, age of patient, histological type, and year of treatment.