Mammographic parenchymal pattern and the risk of breast cancer
Wilkinson, E.; Clopton, C.; Gordonson, J.; Green, R.; Hill, A.; Pike, M.C.
Journal of the National Cancer Institute 59(5): 1397-1400
1977
ISSN/ISBN: 0027-8874 PMID: 909098 Document Number: 111704
Xeromammograms of women with breast cancer detected at the National Cancer Institute's Breast Cancer Detection Demonstration Project at the Los Angeles County/University of Southern California School of Medicine were compared with those of control women, chosen from the Project's files, who showed no evidence of breast cancer. The mammograms were categorized according to the classification scheme of J.N. Wolfe into 4 groups (N1, P1, P2 and DY). In group N1, the parenchyma was composed primarily of fat with, at most, small amounts of dysplasia, and no ducts were visible. In group P1, the parenchyma was chiefly fat with prominent ducts in the anterior portion up to 1/4 the volume of the breast, but it also could be a thin band of ducts extending into a quadrant. In group P2, prominent ducts occupied more than 1/4 the volume of the breast. In group DY, severe dysplasia was found. To avoid bias, only mammograms from the breast opposite the breast with cancer were used for the breast cancer patients, and those from the corresponding breasts in the patient's 2 matched controls were utilized. In comparison to N1, the breast cancer risk ratios were 2.1 for P1 and P2 and 5.8 for DY (P < 0.01). The scheme appeared particularly useful in women under 55 yr of age. Mammographic pattern was a risk factor over and above the known risk factors of age at birth of 1st child, age at menopause and family history of breast cancer. In control women, these known risk factors were correlated with the parenchymal pattern but the results were not statistically significant.