(Ivanhoe Newswire) -- A family history of breast cancer is known to elevate a woman's risk for the disease, so most doctors ask women about relatives who may have had the cancer. A new study reveals many women may simply not know about female relatives on their father's side of the family who might have been affected by the disease.

Researchers from Virginia Commonwealth University's Massey Cancer Center in Richmond and the University of Washington in Seattle analyzed data from a survey of women without breast cancer. Results showed 16 percent reported having a female relative on their mother's side of the family who had the disease. Only 10 percent reported a similar relative on their father's side. Women whose mothers had breast cancer were eliminated from the study, so researchers could compare maternal and paternal relatives equally.

Since research suggests women are just as likely to inherit breast cancer from their fathers as their mothers, the investigators believe these findings most likely suggest under-reporting of paternal relatives who had the disease. "A familial breast cancer screening tool should accurately elicit as many relatives with breast cancer as possible," write the authors. "Primary care physicians might pay particular attention to getting information about the father's side of the family since patients may not know that paternal family history is also relevant for their health."

They call for more study to identify new and better ways to ensure paternal history of breast cancer is included in breast cancer screening programs.

SOURCE: American Journal of Preventive Medicine, published online July 25, 2006, Volume 31, Issue 3