Error rate of N.L. cancer tests alarms advocates

Faulty hormone receptor tests disqualified scores of women in Newfoundland and Labrador from receiving potentially life-saving treatment for breast cancer, court documents show.

The documents also show the error rate for a controversial series of tests completed over an eight-year period is much higher than expected.

For almost two years, the Eastern Health regional authority has been grappling with erroneous hormone receptor testing. A class action lawsuit has been filed over the tests, which have involved hundreds of women.

When testing began in 2005, Eastern Health predicted that about 10 per cent of the tests would be wrong. But an affidavit filed by Eastern Health as a response to the lawsuit shows the error rate is actually much higher.

Of 763 patients who tested negative, 317 turned out to have been given wrong results.

"It looks like there was upwards of 42 per cent of the tests results were actually wrong, and that's a pretty startling number," said Peter Dawe, executive director of the Canadian Cancer Society.

"My initial reaction was that I was surprised that the numbers were so high."

Dawe and other cancer advocates have been lobbying for more information about the hormone receptor tests since the summer of 2005, when Eastern Health arranged with Mount Sinai Hospital in Toronto to retest samples.

According to a February 2007 affidavit signed by Heather Predham, assistant director of quality and risk management with Eastern Health, of the 317 patients with wrong results, 104 patients required a change in treatment.

Of those, 96 were prescribed Tamoxifen, a drug therapy considered one of the best options for blocking the hormones that promote cancerous cell growth.

Gerry Rogers, a St. John's filmmaker who is one of the more than 40 women involved in the class action suit, said she was deeply disturbed by the findings.

"When people are sick and you've had cancer, people are so afraid, you're just so afraid you automatically think you're going to die," said Rogers.

"So you need to have faith and trust in the medical system, in your doctors, and I really have a lot of respect and trust in the doctors who have taken care of me. But it kind of shakes your foundation when you know it's still a bit of a crapshoot and then this stuff happens," she said.

Eastern Health is not commenting on the testing while the matter is in court. A judge is expected to decide later this month whether the class action lawsuit will proceed.

Eastern Health is not releasing the results of tests that were redone for 176 patients who died since their original tests.