ABSTRACT
To assess the importance of various risk factors for breast cancer in women with benign proliferative breast lesions, the authors reevaluated 10 366 consecutive breast biopsies performed in women who had presented at three Nashville hospitals. The median duration of follow-up was 17 years for 3303 women, 1925 of whom had proliferative disease. This sample contained 84.4% of the patients originally selected for follow-up. Women having proliferative disease without atypical hyperplasia had a risk of cancer that was 1.9 times the risk in women with non-proliferative lesions (95% confidence interval (CI) 1.2-2.9). The risk in women with atypical hyperplasia (atypia) was 5.3 times that in women with non-proliferative lesions (95% CI 3.1-8.8). A family history of breast cancer had little effect on the risk in women with non-proliferative lesions. However, the risk in women with atypia and a family history of breast cancer was 11 times that in women who had non-proliferative lesions without a family history (95% CI 5.5-24). Calcification elevated the cancer risk in patients with proliferative disease. Although cysts alone did not substantially elevate the risk, women with both cysts and a family history of breast cancer had a risk 2.7 times higher than that for women without either of these risk factors (95% CI 1.5-4.6). This study demonstrated that the majority of women (70%) who undergo breast biopsy for benign disease are not at increased risk of cancer. However, patients with a clinically meaningful elevation in cancer risk can be identified on the basis of atypical hyperplasia and a family history of breast cancer.
