[Growth rate and natural history of breast cancer]

Available data on growth rate of human breast cancers and their kinetic of cell proliferation were reviewed. Breast cancers are among those human cancers with the longest doubling time and the lowest labelling index, however the spread of the individual values is especially large. Analysis of the data indicate that half of the metastases began to grow more than about two years before the time when the primary tumor reached a clinically detectable size. The prognostic influence of the delay between the time when the tumor reached a clinically detectable size and the treatment is discussed. A correlation is observed between the growth rate of the primary tumors and the mean survival of the deceased patients. This is probably due to correlation between the growth rates of the primary and of the metastases. The growth rate of the primary seems to have little influence, if any, on the probability of metastatic dissemination per tumor cell. This probability varies widely among various clinical types of breast tumors and is probably correlated with other parameters such as the presence of an inflammatory reaction.