Health Minister Yves Bolduc discussed the breast cancer retests on Wednesday. (CBC)

Thirty-nine Quebec women with breast cancer did not receive the right treatment because of erroneous pathology hormone marker tests, the province's Health Ministry has confirmed.

Some 3,000 Quebec women were properly diagnosed with breast cancer last year but the 39 were given false negative pathology test results that determined their course of treatment, according to new laboratory results released Wednesday by the ministry.

Based on the new test results the treatment for the women will be altered, said Quebec Health Minister Yves Bolduc.

However, of the 39 women, five have died since the faulty tests were revealed earlier this year, but there is no way to link their deaths to erroneous pathology results, he said.

The rate of faulty pathology tests falls below the acceptable margin of error in medicine, said Bolduc, who is a physician.

"We know that our tests are very good, but even if they are very good, they are not perfect," he told a news conference in Quebec City.

"It's impossible that that the tests would be perfect. What we said is that in the condition that we are in now, the tests that we did in the last year, in our laboratory...are the best in the world. And this is what the study said to us."

Tested in Seattle

The study — a series of retests of some 3,000 breast cancer cases in Quebec — was done at PhenoPath Laboratories in Seattle this fall, after the Quebec government requested a second round of pathology exams.

That request was prompted by a study published last spring, in which a Quebec pathologist found discrepancies between different laboratory test results across the province.

Quebec health officials revealed the results of the Seattle pathology tests on Wednesday, six months after Bolduc promised a full review.

The Seattle tests showed that 37 women suffered from cancer that would better respond to hormone treatment. In the other two cases, the tests recommended treatment with breast cancer drug Herceptin.

The health minister said all women affected by the erroneous tests would be fully informed about the treatment discrepancy. In cases where the women died, their families would also be contacted.

Earlier media reports indicated the government was not going to contact families of patients who had died during retesting for "compassionate reasons."

The treatment received by thousands of women was questioned earlier this year, after a report from a Quebec pathologist suggested there were disparities in their breast cancer tests.

Last summer, Quebec's Health Ministry confirmed that as many as 3,000 pathology tests done between April 2008 and June 2009 may have been mishandled.

The tests are done to determine the appropriate course of chemotherapy treatment according to the type of breast cancer.

The province's medical specialists' federation is already criticizing how Quebec has handled the retesting.

Federation president Dr. Gaétan Barrette told CBC News that the province's Liberal government wants to keep the results quiet to avoid potential lawsuits.

A class-action lawsuit relating to the tests has been filed in Quebec.

With files from The Canadian Press