Study Finds Regular Mammograms For Those in Their 40s is Linked with Lower Advanced Cancer Rates

Mammogram recommendations are not always uniform, with some agencies and groups pushing for starting at 40, some at 45, and some at 50. There are also different guidelines for those who may be at higher risk. A new study out of Canada, however, finds that regular screenings in women in their 40s may lead to fewer issues later on.

Researchers from the University of Ottawa compared breast cancer statistics for women in Canadian provinces that regularly screen at the ages of 40-49 and those that do not. Results from the journal Current Oncology show that there are a lower proportion of more advanced cancers in areas that screen earlier.


Dr. Anna Wilkinson, co-lead author and associate professor in the Faculty of Medicine at the university, says, “This is the first Canadian study to show that screening policies for women 40-49 impact women 50-59. 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.”

The Canadian Task Force on Preventive Health Care’s current guidelines are that women should begin regular mammograms at the age of 50. However, they do say that women in their 40s who want to be screened due to values and preferences should discuss the matter with their doctors. Regardless, the study authors note that many Canadian provinces still send out screening reminders to these younger women.

In those that do, the team found that there were lower proportions of stage 2, 3, and 4 breast cancers in women in their 40s, as well as lower proportions of stages 2 and 3 in women in their 50s. The data came from 55,490 women between the ages of 40 and 59 who were diagnosed between 2010 and 2017 and whose records are in the Canadian Cancer Registry.


The team also wanted to zero in on what happened after Canadian guidelines were changed in 2011 to recommend against screening women in their 40s. They found that since then, there has been a 13.6% decrease in stage 1 incidence in this age group, along with a 12.6% increase in stage 2. For those in their 50s, there was a 3.1% increase in stage 2 incidence. And in the provinces which did not conduct regular screenings of the 40-49 age group, women in their 50s saw a 10.3% increase in stage 4 cases between 2011 and 2017.

As stage at diagnosis has implications for survival, the team says it may be time to reevaluate current Canadian recommendations.

Dr. Jean Seely, co-author and Head of Breast Imaging at The Ottawa Hospital, says, “This is a great example of the benefit of using Canadian Cancer Registry data housed at Statistics Canada to take advantage of studying the effect of different policies regarding ages to start screening. Our findings align with recently updated USA National Comprehensive Cancer Network guidelines that recommend annual screening mammography for average risk women beginning at age 40.”


Dr. Seely adds that further research needs to be done to see how diagnosing these cases earlier impacts fatality rates and improved long-term outcomes.

If you’d like to screen regularly in your 40s, talk to your doctor.

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