Having a family history of prostate cancer could increase a woman's risk of developing breast cancer, a new study found.
The findings suggest patients' cancer risk should be assessed based on their complete family history of all cancers, not just in family members of the same gender, a news release reported.
A team of researchers looked at a sample of 78,171 women who were enrolled in the Women's Health Initiative Observational Study between 1993 and 1998 and did not have breast cancer at the start of the study. Over the course of an almost decade-long follow-up there were 3,506 new cases of breast cancer among the participants.
The data revealed a family history of prostate cancer in first-degree relatives increased women's risk of breast cancer by about 14 percent after adjusting for other risk factors. A family history of both breast and prostate cancer was determined to raise individual breast cancer risk by as much as 78 percent, and these links were stronger among African American women when compared with white women.
"The increase in breast cancer risk associated with having a positive family history of prostate cancer is modest; however, women with a family history of both breast and prostate cancer among first-degree relatives have an almost 2-fold increase in risk of breast cancer," said Jennifer L. Beebe-Dimmer, of the Barbara Ann Karmanos Cancer Institute and Wayne State University School of Medicine.
The researchers noted the findings are important because physicians often ignore certain cancer diagnoses in family histories, especially if they occurred in members of the opposite sex.
"These findings are important in that they can be used to support an approach by clinicians to collect a complete family history of all cancers-particularly among first degree relatives-in order to assess patient risk for developing cancer," she said. "Families with clustering of different tumors may be particularly important to study in order to discover new genetic mutations to explain this clustering."
The findings were published in a recent edition of the journal Cancer.
