To study the significance of family history in the incidence of breast cancer, we investigated the family histories of 509 patients (breast cancer : 321 cases, benign disease : 188 cases).
The conclusions from the above investigation were : 1) Family histories of breast cancer and malignant neoplasm generally were more frequent in patients with breast cancer than in those with benign disease. 2) The incidence of familial breast cancer tended to be higher in younger age groups and premenopausal cases, but the incidence of all malignant neoplasma tended to be higher in older age groups and postmenopausal cases.
These facts suggest that hereditary factors affect the incidence of breast cancer. A family history of breast cancer increases the incidence of breast cancer in the family, and it also has a risk of onset in early years.