At least one Newfoundland woman was treated for breast cancer in the 1990s by the Eastern Regional Integrated Health Authority even though she never actually had the disease, a class-action lawsuit alleges.

The lawsuit also alleges a failure of quality control by the health authority in the testing of breast cancer tissue specimens for estrogen and progesterone hormone receptivity.

St. John's lawyer Ches Crosbie claims those misdiagnoses resulted in needless surgeries and chemotherapy treatments for the patients, as well as inflicting unnecessary mental distress on them.

Crosbie said there are three groups of women involved in the suit:

• Those who say they suffered mental stress after learning their tissue samples were being retested.
• Those whose say their estrogen and progesterone receptor tests were changed from negative to positive and they were unnecessarily treated with chemotherapy.
• Those who were allegedly misdiagnosed with breast cancer.

Myrtle Lewis of Conception Bay South in Newfoundland is one of the women involved in the class-action suit. She said she had a double mastectomy, only to find out seven years later that the surgery was unnecessary.

Lewis said she is not suing for the money, but to help ensure such incidents do not happen to anyone else in the future.

There's nothing that'll ever replace what I've lost," she said. "But if it's going to help somebody else, some other woman out there, I say to them, 'Make sure, make sure you get the second opinion.' "

The lawsuit was filed last month by plaintiff Verna Doucette on behalf of a group of women who feel they suffered as a result of testing problems in the pathology department.

Crosbie estimates that as many as 1,000 women may be involved.

According to Doucette's statement of claim, which was filed in the Supreme Court of Newfoundland, Eastern Health noticed in 2005 that some patients diagnosed with breast cancer since 1997 were not responding as expected to treatment.

The statement says Eastern health sent cancer tissue samples collected from approximately 1,000 patients to the Mount Sinai Laboratory in Toronto for retesting.

Doucette alleges in the claim that the Mount Sinai retesting showed an error rate of at least 10 to 20 per cent when testing for estrogen and progesterone receptors.

The statement of claim does not specify how much money the group is seeking in damages.

Crosbie said that, as of Thursday, Eastern Health had not yet responded to the allegations.