Breast cancer in men is rare, but it does happen. Less than 1% of all breast cancers occur in men. About 2% of all breast cancer diagnosed in the United States is in men.
While the link between estrogen and breast and ovarian cancer in women has been known for many years, it’s been unclear if there is a link between male breast cancer and estrogen.
Now an international study has found that men with naturally high levels of estrogen may have a higher-than-average risk of breast cancer.
The research was published online on May 11, 2015 by the Journal of Clinical Oncology. Read the abstract of “Prediagnostic Sex Steroid Hormones in Relation to Male Breast Cancer Risk.”
In the study, the researchers combined data from seven studies on male breast cancer. The studies took place in several countries around the world, including the United States, Norway, and other European countries.
The researchers compared the estrogen levels of 101 men who developed breast cancer with 217 men who hadn’t developed breast cancer.
The average age of the men in the study was about 51, and the average age at diagnosis was about 67 years.
Men with the highest levels of estrogen in their blood were about 2.5 times more likely to develop breast cancer than men with the lowest estrogen levels.
“We've shown for the first time that just like some forms of the cancer in women, estrogen has a big role to play in male breast cancer,” said Tim Key, one of the study’s authors and a professor at the University of Oxford. “So now the challenge is to find out exactly what this hormone is doing to trigger this rare form of the disease in men and why some men have higher levels of estrogen in their blood. Our discovery is a crucial step forward in understanding the factors behind male breast cancer."
To learn more about breast cancer in men, including treatments and symptoms, visit the Breastcancer.org Male Breast Cancer pages.