PARIS--When counseling women about breast cancer risk, physicians face the difficulty of translating relative risks into real-life prospects, Michael Baum, CHM, FRCS, of the Royal Marsden Hospital, London, said in a presentation at the Eighth Annual European Cancer Conference (ECCO-8).
The lay public's perception is that about one in 12 women will develop breast cancer at some point in life, Prof. Baum said, and, thus, a woman who is told that she has a threefold increase in risk may go through life believing that her chances of developing breast cancer in any one year are 25%.
"This is cruel and we have ourselves to blame for all the fear that's out there in the community," he said. "The public has difficulty in translating relative risk into absolute risk."
Prof. Baum's counseling strategy is to advise women not to think about their lifetime risk, but about what may happen in the next decade. For example, he said, a normal 50-year-old woman has a 2% chance of developing breast cancer over the next decade, and, thus, even a threefold increase in the odds means only a 6% risk.
"Counseled that way, most of my patients can live with that risk without being forced into inappropriate and experimental risk avoidance schemes," Prof. Baum said.
It may be more difficult, he acknowledged, to counsel the young patient with a suggestive family history. He noted that computer programs are now available that can calculate the probability of penetrance of a dominant gene.
A woman with a family history of breast cancer may have a rare inherited gene with a high penetrance, such as BRCA1, BRCA2, and p53; a common inherited gene with low penetrance; or sporadic mutations due to an inherited deficiency of DNA repair mechanisms, Prof. Baum commented.