Genetic risk: Should doctors warn you about incidental findings?

Incidental findings describe the discovery of a genetic condition that may cause a disease which is unrelated to why a doctor ordered the test for an individual. (Shutterstock)

Do Canadians want their doctors to tell them about genetic risks that might be exposed when screening the genome for an unrelated medical reason? It depends, a new study suggests.

Advances in genomic sequencing technology raise a host of ethical issues about "incidental findings" — the discovery of a genetic condition that may cause a disease unrelated to why a doctor ordered the test in the first place.

For example, a test to determine if there is a hereditary cause of a patient's colon cancer could point to a risk of other diseases, such as Alzheimer's disease, unrelated to the cancer diagnosis.

Next-generation genomic sequencing looks at the whole genome instead of just a region. It's considered better at finding changes than conventional testing. Currently, the technology is used by researchers at hospitals in Canada.

When Dean Regier of the BC Cancer Agency in Vancouver and his team surveyed 1,200 adults in English and French about various scenarios, most valued receiving information about high-risk disease disorders with severe health consequence with an effective medical or lifestyle intervention and at least an 80 per cent lifetime risk.

There's a net societal benefit to offering patients the choice to learn the information, Regier said.

But not everyone wants to receive incidental findings regardless of its potential implications for health care, he added. For disorders with no medical treatment available or mild health effects, participants said the incidental findings were less useful and could reduce well-being.

Regier called the research in Monday's Canadian Medical Association Journal timely given there's been a lot of debate among clinicians about which incidental findings to share with individuals. So far, the decision has generally been not to, given clinicians have a duty to prevent harm by telling patients about incidental findings.

"It will give voice to the public and to patients in terms of they should be offered a choice about what types of information they should receive. This is in contrast to the guidelines and a lot of what's done now in terms of making decisions for the patient," Regier, a health economist, said in an interview.

The questionnaire included five characteristics for each choice:

Varying levels of lifetime risk of the disease at some point in the future, ranging from five per cent through 40 per cent, 80 per cent, 90 per cent or higher.
Treatability of the disease (no effective medical treatment or lifestyle change, recommended medical treatment or lifestyle change, recommended effective lifestyle change only, or recommendations for both.)
Severity of the disease (mild, moderate, severe or very severe.)
Carrier status — disease risk doesn't affect you but could affect your family.
Cost to you, ranging from free through $750 or $1,500.

They said more research is needed on the best ways to communicate the range of possible incidental findings.

Participants in the 2013 online survey had more education than the average Canadian, the study said, and tended to be in the middle-income range of $30,000 to $50,000.

The researchers also pointed to a drawback in that what people say they'll choose and what they actually choose in a real-life clinical setting may differ.

The study was funded by the Canadian Centre for Applied Research in Cancer Control.