Breast Cancer in Women with Cystic Disease of the Breast

Abstract

From 1937 to 1960, 1051 women with cystic disease of the breast were hospitalized at the National Cancer Institute of Milan; 1008 of them were followed for a period ranging from 1 to 26 years, with an average of 8.5 years. All cases were histologically proved. Twenty-one of the patients developed a cancer of the breast; 16 in the breast with the cystic disease, 5 in the contralateral breast. In 667 cases the disease was histologically classified as «simple cystic disease »; 12 of these cases had a breast cancer. In 384 cases the disease was classififed as «hyperplastic cystic disease»; 9 of these developed a cancer of the breast. The follow-up of the 1008 cases provided 8539 person-years at risk; the number of the expected breast cases was calculated on the basis of the Dorn and Cutler data on morbidity of cancer in 10 metropolitan areas of the United States. The number of expected breast cancer was 12.2; the number of observed cases was 21, the ratio between observed and expected cases being 1.71.