HEREDITARY BREAST-CANCER IN FINNISH WOMEN

Objective: To estimate the incidence of hereditary breast cancer seen in one Finnish hospital and to study the characteristics of the diseas e. Design: Retrospective questionnaire and study of Finnish Cancer Reg istry. Setting: University hospital, Finland. Subjects: All 669 patien ts operated on for breast cancer 1986-90. Main outcome measures: Type of breast cancer and morbidity in hereditary compared with other forms of breast cancer. The definition of hereditary breast cancer requires that at least three first degree relatives, inclusive of the proband, have breast cancer. Results: Of the 669 patients 495 answered the que stionnaire. Ten patients (2%) were classified as having hereditary bre ast cancer. The remaining 485 patients had other types of breast cance r by definition. Of those that were not hereditary 89 (18%) were class ified as having familial breast cancer. Of the 495 patients 396 (80%) were classified as sporadic. The mean age of the patients at onset of the disease was 56 years in the hereditary group, 55 years in the fami lial group, and 57 years in the sporadic group. One patient (10%) in t he hereditary, five (6%) in the familial, and 17 patients (4%) in the sporadic group had bilateral disease. Ductal carcinoma was most common in all groups of patients with breast cancer. Conclusion: There were no statistical differences in this series in the age at onset, inciden ce of bilateral disease, stage, and histopathology among the groups, a lthough bilateral and lobular cancer were seen more often in the group with hereditary breast cancer.