Genetic testing rates for ovarian cancer low across Ontario

Less than seven per cent of Ontario women with the most common type of ovarian cancer were seen for genetics consultation within two years of diagnosis, despite its high potential for life-saving benefits, a new cohort study has shown.

Women at the highest risk of developing high-grade serous ovarian cancer (HGSC) are those with a mutation in their BRCA (tumour suppression) genes – which can be identified through genetics consultation. Despite the province’s expanding genetic counselling eligibility in 2001 to all women with HGSC ovarian cancer, consultation rates remained low.

The study from Western University, Lawson Health Research Institute and the Institute for Clinical Evaluative Sciences (ICES) Western site in London, Ontario, was published in the March edition of the International Journal of Gynecological Cancer. The researchers examined administrative data of the 5412 patients with HGSC ovarian cancer in Ontario between 1997 and 2011. While the rates of those who were seen by a genetic counsellor rose over the time period peaking at 13.3 per cent in 2011, the numbers remain well below where the study authors believe they should be.

“These numbers show that no matter what centre you are in, there have to be better interventions to help patients see a genetic counsellor,” said Dr. Jacob McGee, associate professor at Western’s Schulich School of Medicine & Dentistry, Lawson scientist,  physician at London Health Sciences Centre (LHSC), and the study’s lead author. “This is something absolutely worth doing because of the impact it has for both the patient’s current treatment and in preventing ovarian cancer cases down the road.”

The identification of a BRCA mutation in an affected individual allows for consideration of treatment with a PARP (poly-ADP-ribose polymerase) inhibitor, a new class of medication found to be beneficial for women with this mutation. It also allows for testing for family members, where the finding of a genetic mutation may be followed by interventions including surgically removing the ovaries and fallopian tubes, which has been shown to drastically reduce mortality rates. For women with the BRCA mutation, there is a 50 per cent chance that they will pass that mutation on to their children and grandchildren.

The study’s authors point to an intervention at LHSC’s London Regional Cancer Centre (LRCP) that has increased the rate of consultation in London to well above the provincial average. The genetics referral process for patients with HGSC was altered from an ‘opt-in’ to an ‘opt-out’ process. This involves automatically forwarding the list of new HGSC ovarian cancer patients to the cancer genetics clinic through an advance directive.  Seeing a genetic counsellor or geneticist becomes the default, with patients stepping outside of the referral process only if there physician cancels the consultation with genetics. In the first year of implementation, 77 per cent of patients at LRCP diagnosed with HGSC completed genetics consultation.

“This process has been surprisingly easy to implement, and we think it could be a good fit for other centres across the province,” said McGee.