Bewildered about when you should get your first mammogram? If you are, it’s not surprising. There are conflicting recommendations. The American Cancer Society recommends women with an average risk of getting breast cancer begin screening at age 45, and the U.S. Preventive Task Force (USPTF) urges against routine screening before age fifty.

Recent research, which is all about numbers, may only add to your confusion.

In a nutshell, the new study led by University of Ottawa professors found that women living in the Canadian provinces who screened annually between the ages of 40 to 49 had lower proportions of advanced breast cancer compared to women aged 50 to 59 from provinces that did not screen with annual mammograms.

More women presented with later stage breast cancer in their fifties after the Canadian guidelines changed in 2011 to recommend against screening women 40-49,

“This is the first Canadian study to show that screening policies for women 40-49 impact women 50-59,” explained Anna Wilkinson, one of the study’s lead authors, in a press statement. “Women who are not screened in their forties present with later stage breast cancer in their fifties,” she added. “This means more intensive treatment and a worse prognosis for these women than if their cancers were diagnosed in an earlier stage.”

The results are based on the data from over 55,000 women between the ages of 40-49 and 50-59 from the Canadian Cancer Registry who were diagnosed with breast cancer between 2010-2017. Wilkinson, an Associate Professor in the Faculty of Medicine at Ottawa, and co-lead author, Jean Seely, found that later screening policies are not always for the better.

Since the Canadian guidelines changed in 2011 to recommend against screening women 40-49, the following happened:

  • Although there was a 13.6 percent decrease in the incidence of stage 1 breast cancer, there was a 12.6 percent increase in stage 2 for women in their forties.
  • For women in their fifties, 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 40-49, the results were somewhat disturbing. There researchers reported a 10.3 percent increase in stage 4 breast cancer in women 50-59 over the six-year period.

This isn’t the end of the Canadian investigation. “Further work will be needed to determine whether finding theses cancers at an earlier stage translates into fewer fatal breast cancers and improved long-term outcomes,” Seely, the Head of Breast imaging at The Ottawa Hospital and Professor at the University of Ottawa’s Faculty of Medicine, said.

Even after reading this article, you may still be confused about when to start getting routine mammograms. Have a discussion with your gynecologist. She or he can help you weigh your risk factors and suggest a timetable.

You can also work on reducing your risk of developing breast cancer. The Centers for Disease Control (CDC) recommends:

  • Maintain a healthy weight.
  • Exercise regularly.
  • Avoid alcohol or limit alcoholic drinks.
  • If you are taking, or have been told to take, hormone replacement therapy or oral contraceptives (birth control pills), ask your doctor about the risks and find out if it is right for you.
  • Breastfeed your children, if possible.
  • Talk to your doctor about further ways you can lower your risk if you have a family history of breast cancer or inherited changes in your BRCA1 and BRCA 2 genes.

The study can be found in the journal Current Oncology.