Genetic test for breast cancer helps women decide if preventive cancer treatment is right for them

A new study by University of Manitoba, CancerCare Manitoba and Mayo Clinic researchers has found that when women at high risk are provided with the results of genetic testing, they are more likely to take preventive medications to reduce their chances of developing breast cancer.

Studies have shown that the risk of breast cancer can be reduced by half using medicine to prevent it. So the research team sought to determine if presenting women with personalized genetic information that identified whether they are at a higher risk of developing breast cancer would change their decision to use preventive medicine.

“What we’re excited about is that we think this can encourage the use of medicines to prevent breast cancer through the use of personalized genetic testing,” said co-principal investigator of the study Dr. Julian Kim, assistant professor, University of Manitoba, Radiation oncologist, CancerCare Manitoba and scientist, Research Institute of Oncology & Hematology.

“There’s a saying that an ounce of prevention is worth a pound of cure. Meaning that it is preferable to prevent breast cancer rather than have a woman endure the troubles of surgery, chemotherapy, and radiotherapy. It also costs less to the health-care system to prevent breast cancer rather than to treat it after it has developed.”

The University of Manitoba and CancerCare Manitoba investigators involved in the study included Drs. Andrew Cooke, Christina Kim, Benjamin Goldenberg and Debjani Grenier. 

Study results will be presented today at the American Society of Clinical Oncology annual meeting in Chicago, Illinois.

Of the 150 study participants, 76 were from Manitoba. Patients were first given a counseling session using their clinical risk estimates of breast cancer and were offered breast cancer preventive medicines.

Patients then completed a survey to assess their intent to take a medicine. A genetic analysis was performed, and the genetic risk of developing breast cancer was calculated. Patients were shown their test results and later surveyed on their intent to take medicine. The risk score increased breast cancer risk estimates for 55.6 percent of study participants. After counselling, the participants’ intention to take preventive medications change significantly, with 41.9 per cent of those with higher risk scores more inclined to take medication.

“This study represents a big first step, but it needs to be studied further prior to being ready for prime time” Kim said. “Not a lot of women are using medicine to prevent breast cancer, and anything we can do to reduce breast cancer is a step in the right direction.”

UM Today Staff