The association of pathologic and mammographic characteristics of primary human breast cancers with "slow" and "fast" growth rates and with axillary lymph node metastases.

This article reports statistically significant associations existing between the clinical, mammographic and histopathologically classified properties of mammary cancers occurring in the population of 10,120 women screened in the BCDDP at the University of Louisville over a 5-year period and the propensity to grow "fast" and "slow" and metastasize or not metastasize to the axillary lymph nodes. Fast cancers, divided into two defined subsets as "fast 1" and "fast 2," are those surfacing in the intervals between mammograms. The faster cancers exhibited a significant absence of calcification, were discovered in younger patients and resulted in a shorter 5-year cumulative survival rate (fast 1 = 74 +/- 9% to slow = 94 +/- 4%). In addition to growth rates, another index of virulence in small cancers is the early appearance of metastases in the axillary lymph nodes. The absence of microscopic calcifications and the presence of lymphatic invasion around the primary cancer site were significantly associated with the presence of axillary metastases. Other factors associated with the occurrence of axillary metastases were a higher mitotic index, poor cellular differentiation and a larger size of cancer at diagnosis. The author's results confirm that interval surfacing cancers are biologically different and are not comparable to cancers discovered by scheduled screens. Cancers that metastasize to lymph nodes while very small have properties in common with these interval surfacing and, presumably, faster growing cancers.