Annual screening before age 50 leads to lower percentage of advanced breast cancer

National Cancer Institute/Unsplash

New research has found that screening women aged 40 to 49 had lower proportions of advanced breast cancer compared to women aged 50 to 59 from areas that did not hold annual mammograms.

The study, focused on women in Canadian provinces and mammogram screening practices, was published in the journal Current Oncology, and led by researchers at the University of Ottawa in Canada. Investigators revealed lower proportions of stage 2, 3 and 4 breast cancer in women 40 to 49 and lower proportions of stage 2 and 3 breast cancer in women 50 to 59 from provinces which screened the 40 to 49 age subset annually.

“This is the first Canadian study to show that screening policies for women 40 to 49 impact women 50 to 59,” said Anna Wilkinson, MD, an associate professor in the Faculty of Medicine at uOttawa and co-lead author of the study in a statement. “Women who are not screened in their 40s are presenting with later stage breast cancer in their 50s. This means more intensive treatment and a worse prognosis for these women than if their cancers were diagnosed at an earlier stage.”

Wilkinson and her team reviewed the data of 55,490 women between the ages of 40 to 49 and 50 to 59 from the Canadian Cancer Registry who were diagnosed with breast cancer between 2010 and 2017. They evaluated the impact of the 2011 Canadian breast cancer screening guidelines by looking at changes in the incidence of breast cancer by stage from 2011 to 2017.

The authors found that since Canadian guidelines changed in 2011 to recommend against screening women 40 to 49, there has been a 13.6 percent decrease in incidence of stage 1 and a 12.6 percent increase in stage 2 for women in their 40s. For women in their 50s, the incidence of stage 2 increased by 3.1 percent over the same period. In provinces which did not continue to have organized screening programs for women 40 to 49, there was a 10.3 percent increase in stage 4 breast cancer in women 50 to 59 over the six years.

“Further work will be needed to determine whether finding these cancers at an earlier stage translates into fewer fatal breast cancers and improved long-term outcomes,” said Jean Seely, MDCM, FRCPC, head of Breast Imaging at The Ottawa Hospital and professor at uOttawa’s Faculty of Medicine, and co-lead author of the study in a statement.