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Should patients be allowed to opt out of routine testing of colorectal tumours for genetic linkage?

Toronto, October 6, 2016

By Leslie Shepherd

Dr. Yvonne Bombard
Dr. Yvonne Bombard

Health-care providers support routine testing of colorectal tumours to identify more individuals who have the most common genetic condition responsible for such cancers, a new study suggests.

And few felt patients should have the right to opt out of this test that would determine whether they have Lynch Syndrome, according to the study by Dr. Yvonne Bombard, a genomics and health services researcher in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital.

The study was published online today in the journal Genetics in Medicine.

Lynch Syndrome, which is caused by defects in four genes, accounts for about three to five per cent of colorectal colon cancer cases. People who carry those mutations are at an increased lifetime risk of several cancers, including a 12-48 per cent risk of colorectal cancer and a 15-54 per cent risk of endometrial cancer. Early detection and monitoring can reduce the incidence of colorectal cancer: when detected early, as Stage 1 colorectal cancer, an estimated 90 per cent of people will survive.

Dr. Bombard interviewed surgeons, genetic counselors, oncologists, primary care physicians and gastroenterologists for their views and experiences on tumor testing, notification of results, counseling patients with Lynch Syndrome and their families, and their vision for the design and implementation of routine testing.

The medical profession has been divided over the need for explicit patient consent to test tumours for Lynch Syndrome. Those who opposed allowing patients to opt out of routine testing said it was akin to other pathology tests, which are not optional, and would help identify and manage more Lynch Syndrome patients and their relatives who might also be at risk.

Those who supported allowing patients to opt out of routine testing of their colorectal tumours referred to the need to protect the few patients who would receive positive results and may suffer distress or insurance discrimination, versus the need to avoid causing unnecessary anxiety to the majority of patients who would screen negative. Also at issue are the significant resources and expertise required to obtain consent.

Once suspected Lynch Syndrome patients were identified, providers also worried about long wait times to get appointments with genetic counselors and about regional variation in access to counselors.

“Providers emphasized that the introduction of routine testing alone would not necessarily improve care overall for Lynch Syndrome patients and their families,” Dr. Bombard said. “They felt that a comprehensive approach was needed to increase awareness of Lynch Syndrome in the wider medical community and that substantial change would need to occur to improve co-ordinated care, adequate resourcing for genetic services and ongoing surveillance, and provider awareness and education of Lynch Syndrome.”

There are limitations to the study: the researchers interviewed a small number of providers. Dr. Bombard said patients’ views were also needed to ensure that their preferences were incorporated into the design of any program.

“Many health-care systems are considering implementing routine testing for Lynch Syndrome for patients with cancer to improve identification of families at high risk of developing colorectal cancer for more intensive screening,” said Dr. Nancy Baxter, chief of the General Surgery Department at St. Michael’s and one of the paper’s co-authors. “This research will help guide how these programs should be developed.”

This study received funding from Cancer Care Ontario and the Ontario Institute for Cancer Research.


This paper is an example of how St. Michael's Hospital is making Ontario Healthier, Wealthier, Smarter.

About St. Michael's Hospital

St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael's Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.

Media contacts

For more information or to arrange an interview with Dr. Bombard, please contact:

Leslie Shepherd
Manager, Media Strategy, St. Michael's Hospital
416-864-6094
shepherdl@smh.ca