Taking a family history is one of the most accessible genomic screens for breast cancer. However, a history of cancer on the paternal side may not be as well reported.
In a study published in the September issue of the American Journal of Preventive Medicine, researchers from the Virginia Commonwealth University Massey Cancer Center and the University of Washington, Seattle found that subjects reported fewer family members with breast cancer on their father's side than their mother's. The authors point out that on a population basis, women should have equal numbers of maternal and paternal extended relatives (not including mothers) with breast cancer. This under-reporting could have serious consequences for the accuracy of screening for breast cancer.
Using survey data from April 2003 to March 2005 for Women's Health Clinic patients without breast cancer, researchers found that while 16% of the participants reported a maternal relative with breast cancer, only 10% reported a paternal relative. Because mothers are much more likely to develop breast cancer than fathers, participants who reported a mother with breast cancer were excluded from the study.
There may be multiple explanations for this unexpected discrepancy. For this particular study, the family histories might be accurate. This would lead to a conflict with current thinking about the inheritance of breast cancer risk. Alternatively, excessive reporting of maternal cancers could have affected the data, but earlier studies of family history indicate that breast cancer reporting tends to be accurate. Finally, men may not be aware of familial breast cancer risk and may not communicate this information to their relatives. This factor could be important where fathers are not present in the home or are unknown to the child. This would contribute to inaccuracy of family history, although misinformation (as opposed to lack of information) about paternity should not affect the maternal paternal ratio.
Writing in the article, John M. Quillin, PhD, suggests, "The most likely explanation for these findings may be under-reporting of breast cancer on the paternal side. Future studies are needed to look for modifiable explanations (e.g., genetics education, family communication specifically for maternal and paternal relatives, or medical documentation) of the discrepancy in the reporting of family history of breast cancer to improve the sensitivity of the family history screen."
Dr. Quillin continues, "Disease prevention scientists need to be mindful of this discrepancy when using reported family history to design and implement breast cancer health interventions. 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."