Women in Manitoba and Saskatchewan are more likely to die from breast cancer, while women in Alberta and Quebec are most likely to be diagnosed with it, a recent Statistics Canada study says.
The study looked at rates of breast cancer diagnoses and mortality by region.
Montreal, Toronto and Vancouver had the lowest rates of breast cancer deaths, while deaths were highest in rural Eastern Canada.
Cancer researchers say the data point to gaps in breast cancer screening and treatment across Canada.
“If you have an area where there’s a higher instance, you need more resources to invest to help diagnosis and treatment,” said Dr. Jean Seely, head of breast cancer imaging at The Ottawa Hospital and a professor at the University of Ottawa.
Regional variation
Breast cancer is the most common cancer for Canadian women. In 2024, 30,500 women were diagnosed with the disease and 5,500 died from it.
The median age at diagnosis is nearly 63.
“Breast cancer incidence and mortality have decreased over the last decade, [but] national-level estimates mask underlying variability, including variability by age, socioeconomic characteristics, and geography,” the study says.
This latest research “support[s] the case that place-based risk factors should be incorporated into breast cancer risk prediction and screening strategies,” Dr. Ivan Litvinov, a cancer researcher at McGill University, told Canadian Affairs in an email.
“Cancer is driven, in many ways, by exposure,” he added in an interview. A person’s environment, including high pollution or being part of a culture that regularly drinks alcohol, can increase someone’s cancer risk, he says.
Stage at diagnosis
Where women live influences whether breast cancer is diagnosed at a more treatable or advanced stage.
Women in Manitoba and Saskatchewan were more likely to have their cancer diagnosed at Stage 4, the most advanced stage. This may be one reason why breast cancer mortality rates were higher in those provinces, the report says.
Women in large urban centres with high levels of employment and large immigrant or racialized populations were more likely to have their breast cancer detected at earlier stages.
This may be because of greater access to breast cancer screening, says Seely.
“Rural populations tend to be away from some of the medical centres … so [location] may be a factor,” she said.
Her past research has shown that women who live in provinces that offer breast cancer screening for women in their 40s have higher chances of survival.
Litvinov says that more provinces should invest in mobile screening units. A similar program exists for skin cancer, and that model could be useful for breast cancer screening, he says.
Access to breast cancer screening is improving. Most provinces now allow women to start receiving mammograms at age 40. And women under 40 who have concerns about breast cancer can request mammograms.
But access to screening can vary within provinces, says Seely, noting it is “a bit of a postal code lottery.”
Women older than 75 are typically not included in screening programs because research into breast cancer screening has historically not included these women, Seely says.
She says more work needs to be done to expand breast cancer screening to these women. The data show women over 80 were diagnosed with Stage 4 breast cancer at a higher rate than other age groups.
‘Agency’
The study could help people make better health-care choices, says Litvinov.
“We all have agency,” he said. For example, if a woman lives in an area with little access to mammograms, she can have one done when she is in a centre where they are more available.
Seely says that understanding the geography of breast cancer can help governments allocate resources better. But individuals should not think their location automatically increases their risk.
“I don’t think that we should be taking from this study that because you live in this area where [the rate of cancer is] going to be higher, that you’re personally at higher risk,” she said.
“You might be if there’s other factors like environmental [factors]. But [the research] may be a good way for our health-care [policymakers] to say, ‘OK, this area needs more investment.’”
