Quebec's health minister said he's very concerned about a report that suggests a high incidence of mistakes in breast cancer diagnostic tests.

Pathologist Louis A. Gaboury conducted the study on diagnostic tests (CBC)Yves Bolduc said he's reviewing the report that found as many as 15 to 20 per cent of hormone receptor tests given to women with breast cancer may have been erroneous, which means the wrong chemotherapy could have been administered.

The report, led by the Quebec Association of Pathologists, was based on a Radio-Canada investigation probing pathology laboratories in the province.

Bolduc said his priority is to review the report's methodology and verify its findings independently.

"We knew there were improvements that need to be made in pathology laboratories," but his department was never aware there were erroneous diagnoses, he told CBC's French-language service.

Quebec premier Jean Charest said the province "will do whatever needs to be done," once the report is reviewed. "If there are things to be changed, we will do it."

The province's federation of medical specialists said it has warned the government for years about how a shortage of pathologists in the province could compromise the work they do.

"Why is it that in Quebec you have to have a public drama over something before something is done? Ask them," said Gaëtan Barette, president of Quebec's Federation of medical specialists.

Health Minister Yves Bolduc speaks to reporters about the study (CBC)Hormone receptor tests help doctors choose the right kind of treatment for breast cancer tumours.

If the report is accurate, hundreds of women in Quebec may have been given the wrong treatment for breast cancer.

"If we think there's a 10 to 30 per cent variation [in the results], then it's a significant number of people out there with a wrong diagnosis" said Louis Gaboury, president of the pathology association, which led the study.

Chronic understaffing and funding are at the root of the problem, Gaboury said.

Parti Québécois health critic Bernard Drainville called for a quality control program to ensure standardized procedures in pathology labs.

About 6,000 Quebec women are diagnosed with breast cancer every year.

Breast cancer advocacy groups said they are dismayed by the report's findings.

"It's a very awful thing to think that there's not enough funding to be doing testing correctly and to have reliable testing," said Fiona Hanley, a board member at Breast Cancer Action Montreal.

"We want to make sure that when women do have treatment for cancer that the right kind of treatment is given because the treatments can have very serious consequences on the body because they can cause cardiac problems for example," she told CBC News.

A similar situation in Newfoundland and Labrador sparked public uproar, when Eastern Health's pathology lab turned over inaccurate hormone receptor tests to almost 400 patients over an eight-year period. More than 100 women died.

Worried that the same problem could occur in Quebec, the province's pathology association had 15 breast cancer tissue samples retested for hormone receptors by a second laboratory.

With files from The Canadian Press