Radiographic parenchymal patterns in Japanese females as a risk factor for breast carcinoma.

Wolfe has reported that his classification of xerographic parenchymal patterns of the breast was of value in screening programs. However, there has been no attempt to confirm his work in Japan. Therefore, we investigated the relationship of breast parenchymal patterns to breast carcinoma prevalence in Japanese females. In the cancer patients, the P2 pattern was the most dominant pattern (49.4%), followed by the DY pattern (23.6%), the P1 pattern (14.0%), and the N pattern (13.0%). In the group without carcinoma, the dominant pattern was the N pattern (45.2%), followed by the P1 pattern (26.9%), the P2 pattern (21.3%), and the DY pattern (6.7%). The DY pattern was associated with 31% of breast carcinomas that occurred in women under 50 years of age, whereas it was associated with only 13% of breast carcinomas in women older than 50 years. Conversely, the P2 pattern was associated with 58% of the breast carcinomas occurring in women over age 50 years compared to 41% of those occurring in women younger than age 50. More than 70% of the patients with breast carcinoma who were between 30 and 59 years of age demonstrated the P2 and DY patterns. In the patients with breast carcinoma who were over 60 years of age, the incidence of these patterns was somewhat lower (55.6%).