The review for possible errors in 3,500 CT scans and mammograms by a Toronto-area radiologist highlights a critical problem at Canadian hospitals: the lack of national oversight standards for diagnostic tests, radiologists and medical leaders say.
Time and time again across the country, they say, high-profile problems involving diagnostic tests result in medical errors and missed or inaccurate diagnoses, but there is no national system to ensure that mistakes are caught.
That means in many cases it is left to hospitals to determine what quality-assurance measures should be in place – which creates vulnerabilities when oversight is lax, said Matthew McInnes, radiologist and residency program director at the University of Ottawa.
"Usually, there's a systemic reason why these errors occur," he said.
CT scans, mammograms, X-rays and other diagnostic tests increasingly dictate what diagnosis or care patients will receive. But interpreting test results is highly complex. Although various health-care institutions and provinces have been making efforts to boost quality assurance mechanisms, this week's announcement is a reminder that more work needs to be done, said Mark Prieditis, president of the Ontario Association of Radiologists.
"This whole area is evolving very quickly," Dr. Prieditis said. "It sounds like we really should be making this a priority."
Trillium Health Partners announced this week it is reviewing 3,500 computed tomography scans and mammograms after problems were found with the work of radiologist Ivo Slezic, a 33-year employee who worked at Mississauga Hospital and Queensway Health Centre.
Concerns about Dr. Slezic's work arose March 28 after what Trillium described as a routine quality assurance review revealed a patient had been misdiagnosed, prompting the hospital to launch a wider review of scans conducted between April 1, 2012 and March 31, 2013.
The hospital has not revealed details of the misdiagnosis or any specifics about what they call "performance issues" with the radiologist's work.
Trillium did not inform Ontario's Ministry of Health about the situation with the possibly misdiagnosed test results until late August, but said it removed the radiologist's hospital privileges after a two-month internal probe.
One woman, Houda Rafle, 28, told a Toronto television station that she was given a clean bill of health after a CT scan in March, only to find out recently that she did indeed have cancer at the time, and it has gotten worse.
"The tumour was present in March, and unfortunately because there was a six-month duration it had now spread to my lungs and is now Stage 4," Ms. Rafle said.
There have been several high-profile problems involving diagnostic tests in Canada in recent years. Last year, a radiologist in Quebec missed dozens of cases of breast cancer over a period of two years. And in 2009, a public inquiry in Newfoundland and Labrador determined there had been more than 400 cases of misdiagnosed breast cancer from 1997 to 2005, with some of the patients dying as a result of lack of proper care.
Andrew Padmos, CEO of the Royal College of Physicians and Surgeons of Canada, said many hospitals have taken steps in recent years to improve quality assurance for diagnostic tests.
But, Dr. McInnes said, without a national, or even a provincial quality assurance standard, it's difficult to tell whether an individual hospital's oversight program is robust, adequate and thorough enough to catch errors.
British Columbia and Alberta recently announced plans to launch a quality assurance program that would require test results to be automatically sent for double-checking by another specialist. The program is the first of its kind in Canada.
Alberta conducted a system-wide review of medical testing in 2011 after reports about 325 patients were misdiagnosed at three hospitals.
Also in 2011, a report in British Columbia found that poor oversight, among other factors, was to blame in the deaths of three patients and the harming of nine more after they were misdiagnosed by three unqualified radiologists.
Cancer Care Ontario and the College of Physicians and Surgeons of Ontario are also working to establish a provincewide quality assurance mechanism for mammography.
Ontario Health Minister Deb Matthews said the system worked when the two Trillium hospitals detected possible errors. "I am interested in learning about what other provinces are doing, but I think it's important to acknowledge our system is quite different, so that quality oversight is happening in our hospitals," she said.
Dante Morra, chief of staff at Trillium Health Partners, said quality assurance reviews are done annually and that none previously raised concerns about Dr. Slezic's ability to read scans.
Attempts to reach Dr. Slezic at his Mississauga home were unsuccessful and he did not return a message. He had been restricted from reading scans since late March and he left Trillium's employ this week, according to Trillium.
Brian Yemen, the chief of diagnostic imaging at Juravinski Hospital and Cancer Centre and McMaster University Medical Centre, is leading the review of the 3,500 scans. He said a team of up to 17 radiologists will attempt to determine whether other errors were made. He anticipated finding that errors increased at some point within the last year, but did not rule out expanding his review to scans Dr. Slezic read prior to April 1, 2012.
Dr. Yemen acknowledges all radiologists will make an error from time to time. "We're all human," he said.
With a report from The Canadian Press