Growth pattern of ductal carcinoma in situ (DCIS): a retrospective analysis based on mammographic findings.

The aim of this study was to obtain information concerning the direction and rates of growth of ductal carcinoma in situ (DCIS). The previous mammograms of 124 women diagnosed with DCIS were examined. If in retrospect calcifications were present on the previous examination, the exact size and position were recorded on both diagnostic and previous imaging. The rates of change and direction of change in extent of calcifications were calculated. 39 women with a diagnosis of DCIS in retrospect had calcifications visible on both their current and prior examinations; these formed the study group. For individual clusters of calcification, change occurred along an axis to the nipple at a mean of 5.5 mm y(-1)and along an axis at 90 degrees to the nipple at 2.6 mm y(-1). Increase in calcifications along the axis to the nipple occurred at 2.6 mm y(-1)toward and 2.8 mm y(-1)away from the nipple. Increase in the axis to the nipple occurred at 1.8 mm y(-1)for low grade, 4.2 mm y(-1)for intermediate grade and 7.1 mm y(-1)for high grade. DCIS growth along an axis to the nipple occurs at over twice the rate of growth in the other direction(s) and growth toward and away from the nipple occurred equally. Growth rates increased with increasing nuclear grade of DCIS. These results validate nuclear grading of DCIS. Additionally, the results suggest that increased importance should be placed on identifying the 'nipple' and 'anti-nipple' margins of DCIS represented by calcifications for both surgical excision and pathological scrutiny.