The breast cancer susceptibility genes BRAC1 and BRAC2 flag a risk for developing breast cancer, especially before the age of 50. Since they were mapped in 1990, it is possible to determine which healthy women might have a greater risk of developing breast cancer young. What, exactly, does this mean? Neil Sharpe’s In Control answers this question.

Sharpe, a genetic counsellor, has produced a readable book covering everything from relaxation exercises for stress and the mechanics of laboratory testing to ideal counselling scenarios. The author understands misconceptions women have about genetic testing and breast cancer. One chapter shows how different presentations of risk influence responses. A lifetime risk of 1 in 9, for example, also means that a woman has an 89% chance of never developing breast cancer, and this risk looks very different when broken down by decades. Why this excellent discussion appears in Chapter 14, well after these probabilities are introduced, is a mystery.

Only 5 to 10% of all breast cancer is thought to be attributable to these altered genes, although some ethnic groups are more likely to have them than the general population. (These genes occur more commonly in Newfoundland than in the rest of the country because of the island’s homogeneous gene pool.) As Sharpe points out, the knowledge that a woman has an altered gene currently has limited application. Women who know may screen for breast cancer more rigorously, but genetic testing does not lead to any treatment or cure.

In Canada, testing for BRAC1 and BRAC2 genes is currently available only to women who participate in research projects. The process involves taking a family medical history, even collecting blood samples from relatives. The reasons why women might want to be tested, and might even decide to be tested but not told the results, are complex, as is the ideal counselling process that should accompany this testing. In Control details every aspect of this process, and should be required reading for any woman who considers being tested for the breast cancer genes.