Here’s something to think about if you’re on a drug called tamoxifen. More than 200,000 Canadian women take it for 5 years to prevent a recurrence of breast cancer. Research now shows that up to 10 percent of them may be doing it for nothing because of their genetic makeup makes them resistant to the drug.
There is a test that shows which patients are less likely to benefit from the drug. But it’s not widely available in Canada. You can get it in the United States, and it’s expensive. You have to send blood samples or cheek swabs to the American labs that perform it.
The test looks for a variation in the gene that controls the activity of a certain enzyme that might make the tamoxifen less effective in combatting cancer.
It’ll cost you $500 cost for the test, and medical oncologists disagree on whether to recommend it to patients. So talk to your doctor if this affects you.
The Canadian Association of Provincial Cancer Agencies hasn’t taken a position because it says the scientific evidence isn’t reliable enough.