Breast cancer test errors prompt probe into Newfoundland lab

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Newfoundland and Labrador's largest health authority has launched an investigation into how a lab misinterpreted the test results of nine breast-cancer patients, a mistake that is reviving memories of the province's past breast-cancer testing scandal and raising questions about pathology standards across the country.

Eastern Health revealed Thursday that nine women had been needlessly treated with Herceptin, a drug that can curb the growth of certain breast cancers but carries risks to the heart, lungs and liver.

The women's breast-cancer diagnoses have not changed. The news means their cancers are not as aggressive as first believed when the tests were misinterpreted.

"No matter what the test is, if you're told you have cancer – where it is, what it is – that's a devastating diagnosis," Vickie Kaminski, the president of Eastern Health, said in an interview. "If you then find out that there's been some difference in the diagnosis, it's unsettling."

Tests on samples of the women's tissue were interpreted by pathologists at the same St. John's lab where a 2009 public inquiry found nearly 400 instances of misdiagnosed breast cancer between 1997 and 2005, with some patients dying because of lack of proper treatment.

This incident involved a different test, but there is a connection to the scandal: The scrutiny that followed the public inquiry led to the quality-assurance checks that uncovered the latest problem.

After a random check from an external lab raised a red flag in December, the authority reviewed the 65 cases in which Eastern Health's lab had used the test since it began offering it in April. It sent 34 tests to a lab in Miami, which confirmed Tuesday that nine were incorrect.The health board informed patients and apologized to them Thursday. None has suffered side effects from Herceptin, but doctors are monitoring them. The St. John's lab will not perform the test again until it pinpoints what went wrong through an investigation.

Martin Trotter, president of the Canadian Association of Pathologists, said catching the misinterpreted tests shows how far Newfoundland has come since the scandal. "Newfoundland is hugely changed since 2007-2008, in the way pathologists are funded, the funding for the system, the transparency for the system and the quality-assurance programs that have been in place," he said. "In order of magnitude, it's [improved] at least 100 per cent."

There have been a slew of high-profile problems with diagnostic testing across Canada recently, most involving CT scans and mammograms misread by radiologists. Problems with anatomical pathology, the science of examining organs and tissues to make a diagnosis, have received less attention.

Some provinces and larger hospitals have embraced quality-assurance regimes that frequently seek second opinions, but pathology still suffers from the same lack of national standards that plagues radiology. "Not having national standards puts the country at risk for the continuation of errors like we've seen," said Dr. Sylvia Asa, medical director of laboratory medicine at Toronto's University Health Network.