Ontario to lower age for breast cancer screening to 40: What to know

Ontario will join several Canadian provinces that offer earlier breast cancer screening.

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Female doctor and mid adult woman during Mammography test in examination room. breast cancer screening
Ontario is lowering the eligibility age for routine breast cancer screening.

Ontario is lowering the eligibility age for routine breast cancer screening.

In a news release on Monday, the province said the minimum age for self-referral for publicly funded mammograms through the Ontario Breast Screening Program will be reduced from 50 to 40, beginning in fall of 2024.

Deputy Premier and Minister of Health Sylvia Jones said in a release "nearly 12,000 women are diagnosed with breast cancer each year, and we know early detection and increased access to care saves lives."

This move will "connect more than 305,000 additional people to the services they need to ensure timely diagnosis and access to treatment as early as possible," Jones added.

The announcement came five months after the United States Preventive Services Task Force (USPSTF) recommended women begin getting screened for breast cancer every two years at the age of 40.

The health panel, which operates independently from the government, said "this new recommendation will help save lives and prevent more women from dying of breast cancer."

In Canada, the current standard is to start at age 50, but accessibility differs by province. Ontario will join several provinces that do offer earlier screening.

Where each Canadian province stands on breast cancer screening

Doctor and patient making a mammography. Canada federally recommends starting routine mammograms at 50, but access differs by province. (Getty)
Canada federally recommends starting routine mammograms at 50, but access differs by province. (Getty)


Publicly funded routine breast cancer screening begins at age 45 in Alberta. Women aged 45 to 74, who live in Alberta and have no symptoms or family history, are eligible for regular mammograms every 2 years.

British Columbia

Regular mammograms are available to B.C. women at the age of 40, every two years. Though available, routine mammograms are still “not recommended” for ages 40-49, but starting at 50.


Manitoba encourages women aged 50-74 to have a screening mammogram every two years. Routine screening is not recommended for the 40-49 age group.

New Brunswick

Women living in New Brunswick can self-refer to a routine mammogram between the ages of 50 and 74. Mammograms are currently available to women aged 40 to 49 with a doctor referral. However, the eligibility age will be lowered to 40 in early 2024.

Newfoundland and Labrador

The breast screening program in N.L. offers routine screening mammography to women aged 50-74 years.

Nova Scotia

Asymptomatic women are recommended to get an annual mammogram in Nova Scotia at the ages of 40-49. Between the of 50 and 74, women are advised to get a mammogram every two years.


Currently, Ontario’s breast cancer screening program allows routine mammograms for women aged 50 to 74. However, in fall of 2024, the eligibility age will drop to 40.

Prince Edward Island

A publicly funded mammogram is available to P.E.I. women annually, between the ages of 40 and 74.


Women in Quebec are eligible for a mammogram to screen for breast cancer between the ages of 50 and 69, every two years.


Routine mammograms in Saskatchewan are available to residents aged 50 to 74, every two-to-three years.

Northwest Territories

The Northwest Territories public health recommends mammograms to women between the ages of 50 and 74, every two years.


There is no organized breast cancer screening program in Nunavut, but mammograms are available annually starting at the age of 40.


Women in Yukon can access routine screening every year between the ages of 40 and 49. Between the ages of 50 and 74, it is recommended at least every two to three years.


Female holding tablet in front of body to display coloured x-ray illustrations made out of hand made paper structures
Here's a roundup of what experts say around breast cancer screening. (Getty)

Benefits of earlier breast cancer screening

"New and more inclusive science about breast cancer in people younger than 50 has enabled us to expand our prior recommendation and encourage all women to get screened every other year starting at age 40. This new recommendation will help save lives and prevent more women from dying of breast cancer," wrote Dr. Carol Mangione, the immediate past chair of USPSTF.

"Compared to older women, women ages 40 to 49 years have a lower risk of breast cancer, but the types of breast cancer that develop are often more aggressive with a poorer prognosis. Furthermore, younger women have a longer life expectancy and fewer comorbidities," according to a study published in the Journal of Primary Care and Community Health.

Important for Black women

"Mayo Clinic supports screening starting at age 40 because screening mammograms can find breast cancer early… Starting mammograms at age 40 may be particularly important for Black women. Black women tend to have breast cancer at a younger age. Black women are more likely to die of breast cancer, compared to people of other races," noted Mayo Clinic (from Dr. Sandhya Pruthi).

Overdiagnosis concerns

"The harms of overdiagnosis are actually almost zero in women in their 40s… If you get breast cancer and you're in your 40s, that is most likely going to actually lead to death rather than a woman in her 70s or 80s, because an older woman has other competing causes of death," Dr. Jean Seely, head of breast imaging at the Ottawa Hospital, told Global News.

Most Canadians agree with lowering

"89 per cent of Canadians believe routine breast cancer screening should begin before the age of 50… 79 per cent of Canadians believe that Canada should prioritize gathering race-based data on cancer screening rates to address a lack of information on racial disparities," according to a survey from Breast Cancer Canada and Angus Reid.

"What the public would like to see is better access to screenings and detection. The sooner we can detect it, the easier the treatment becomes. And I think that message is received, the public knows that," Kimberly Carson, the CEO of Breast Cancer Canada, told the CBC.

Preventative costs over treatment costs

“We know that when we treat a more advanced breast cancer, they're more likely to need chemotherapy, more likely to need to have a full removal of the breast (so) the cost to our health-care system in terms of treating advanced breast cancer is huge," Dr. Jean Seely, head of breast imaging at the Ottawa Hospital, said to CTV. "We looked at the cost of treating a patient with metastatic breast cancer, one patient can cost over $500,000."

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