Breast cancer rates rising among Canadian women in their 20s, 30s and 40s

Rates of breast cancer in women under the age of 50 are rising in Canada according to a study which showed an increase in breast cancer diagnoses among females in their Twenties, Thirties, and Forties.

Led by Dr. Jean Seely, this study published in the Canadian Association of Radiologists Journal reviewed breast cancer cases over 35 years to shed light on trends in breast cancer detection in Canada.

“Breast cancer in younger women tends to be diagnosed at later stages and is often more aggressive,” said Dr. Seely, Head of Breast Imaging at The Ottawa Hospital and Professor in the Department of Radiology at the University of Ottawa. “It’s alarming to see rising rates among women in their Twenties and Thirties because they are not regularly screened for breast cancer.”

Using data from the National Cancer Incidence Reporting System (1984–1991) and the Canadian Cancer Registry (1992–2019) at Statistics Canada, the research team, which included Larry Ellison from Statistics Canada and Dr. Anna Wilkinson, an Associate Professor in the Faculty of Medicine, looked at all women aged 20 to 54 who were diagnosed with breast cancer.

Their findings included:

• For women in their twenties, there were 3.9 cases per 100,000 people between 1984 and 1988, compared to 5.7 cases per 100,000 between 2015 and 2019 for a 45.5% increase.
• For women in their thirties, there were 37.7 cases per 100,000 people between 1984 and 1988, compared to 42.4 cases per 100,000 between 2015 and 2019 for a 12.5% increase.
• For women in their forties, there were 127.8 cases per 100,000 people between 1984 and 1988, compared to 139.4 cases per 100,000 between 2015 and 2019 for a 9.1% increase.

The study’s results show the importance of targeting younger women in breast cancer awareness campaigns and screening programs. Most public health efforts focus on women over 50, but these findings suggest that younger women are increasingly at risk and may benefit from earlier and more frequent screenings.

Improving awareness

The investigators say more research is needed to understand the root cause of rising breast cancer rates among younger women, information that could be used to develop targeted intervention strategies.

“We’re calling for increased awareness among health-care professionals and the public regarding the rising incidence of breast cancer in younger women,” said Dr. Seely, who alongside Dr. Wilkinson have long documented the benefits of early detection with screening for women in their forties.

“We need to adapt our strategies and policies to reflect these changing trends, ensuring that all women, regardless of age, have access to the information and resources they need to detect and combat this disease.”