Breast cancer risks in relatives of male breast cancer patients.
BACKGROUND
Previous studies have provided conflicting results concerning the familial effect of male breast cancer on breast cancer risks in female relatives.


OBJECTIVE
We studied breast cancer risks in first-degree relatives of male patients and compared them with relatives of female patients.


METHODS
Our study included 88 consecutively ascertained male patients and 320 of their first-degree relatives as well as 186 consecutively ascertained female patients and 633 of their first-degree relatives. Observed numbers of breast cancers in relatives were compared with the expected number derived from the Connecticut Tumor Registry. Multiple logistic regression analysis was also performed.


RESULTS
Relatives of male patients exhibited a significant twofold increased risk when compared with expected rates and no difference in risk when compared with that of relatives of female patients. Prostate cancer in the family of a male patient resulted in a significant fourfold increased breast cancer risk compared with a risk of 1.4 in families with no history of prostate cancer. A family history of lung cancer, colon cancer, or melanoma had no effect on increasing risks of breast cancer.


CONCLUSIONS
The familial effect of male breast cancer is the same as that of female breast cancer.


CONCLUSIONS
Any estimates of breast cancer risk provided to individuals should also consider the occurrence of prostate cancer in the family, since prostate cancer appears capable of at least doubling the underlying twofold risk.
Anderson
D E
DE
Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, Houston 77030.
Badzioch
M D
MD
D000367:Age Factors; D001943:Breast Neoplasms / Q000235:genetics*; D005192:Family Health; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000235:genetics; D011471:Prostatic Neoplasms / Q000235:genetics; D012044:Regression Analysis; D012307:Risk Factors