When Should You Start Getting Breast Cancer Screenings?

Breast cancer screening is an important part of healthcare for women and people assigned female at birth, but it can be confusing to know when to start and how often to get screened.  

The National Comprehensive Cancer Network, for example, recommends that women of average risk (or who don’t know their risk) start screening annually at age 40. But the American College of Physicians released new guidelines this year recommending women get breast cancer screenings every two years starting at age 50. 

What are you supposed to believe?

Why is breast cancer screening with a mammogram important?

While medical groups and societies have different recommendations, they all agree that the best tool for screening women of average risk is a mammogram.

What is a screening mammogram?  

“It is an X-ray-based imaging test that can identify breast cancer before it is clinically apparent, meaning before a patient can feel it or before it causes other symptoms,” says Brian Dontchos, MD, a diagnostic radiologist, associate professor of radiology at the University of Washington School of Medicine, and chief of breast imaging at UW Medicine and Fred Hutch.   

Many clinical trials show that mammograms reduce breast cancer deaths.

“The whole principle behind screening for any type of cancer is that the screening test is not invasive, can be applied to a large population of people, and is relatively inexpensive,” says Dontchos. “But the most important part is that it confers a survival advantage by finding cancer early versus finding it later when it’s clinically apparent.”

Finding breast cancer early, when it’s small, confined to the breast and hasn’t spread to nearby lymph nodes or other organs, means it is easier to treat.  

Why do guidelines change and conflict with one another?

Why do guidelines change and even go back and forth over time? It’s due to new information from ongoing studies and clinical trials. For example, the U.S. Preventive Services Task Force — whose guidelines most insurance companies base their coverage on — used to recommend that women at average risk start screening mammograms at age 50, heavily weighing the risk of mammograms overdiagnosing breast cancer, either with false-positive results or identifying cancers that would not end up affecting survival outcomes. Then, in 2024, they lowered the age to 40. 

“This was due to the increasing prevalence of younger patients and minority populations being diagnosed with breast cancer that has been observed in recent years,” says Dr. Dontchos.

On the other hand, the National Comprehensive Cancer Network and American Cancer Society, which are organizations specifically focused on cancer, place more emphasis on finding cancer early and recommend annual screenings instead of every other year. But even those two organizations interpreted scientific evidence differently in some areas, with the former recommending that screenings start at age 40 and the latter at age 45.  

UW Medicine and Fred Hutch Cancer Center, meanwhile, recommend that women at average risk have a screening mammogram every one to two years beginning at age 40. 

Different standards for high-risk patients

The guidelines are mostly in agreement when it comes to screening for women at high risk for breast cancer.  

According to Dontchos, “high risk” includes:  

• Those who have a strong family history of breast cancer, such as a parent who had it
• Those who have specific genetic mutations, such as BRCA1 or BRCA2.
• In some rare situations, those who have had exposure to high levels of radiation when they were children due to the treatment of certain cancers.  

It’s recommended that people in this group get an MRI, or magnetic resonance imaging, which is a highly sensitive test for breast cancer. If you have cancer, an MRI is likely to find it, but it’s much more expensive and time-consuming.  

“We usually reserve screening MRI for patients who have a high lifetime risk of breast cancer,” says Dontchos.  

The starting age and frequency of MRI testing will depend on a person’s individual risk. For example, according to Dontchos, if you have a BRCA1 gene mutation, which is a gene mutation that can convey a very high lifetime risk of breast cancer, you will typically start having screening MRIs at age 25.

Other breast cancer screening tests are not recommended

These days, many other types of scans are being offered that can be attractive to patients because they don’t require breast compression or exposure to small doses of ionizing radiation. But it’s important to be careful about many of them.  

One you might have heard of is a whole-breast screening ultrasound.  

“We do not offer whole breast screening ultrasound at UW Medicine or Fred Hutch because it generates many false-positive results, which cause unnecessary biopsies and unnecessary follow-up examinations,” says Dontchos.

Other scans are being offered commercially, including a form of ultrasound called a Quantitative Transmission (QT) ultrasound, thermography and whole-body MRIs. 

“These tests are unproven, do not have long-term outcomes data and rely on small studies that are very unreliable,” Dontchos says. “We would strongly recommend against utilizing these tests as an adjunct to or as a substitution for screening mammography.”

While mammography uses a small amount of radiation, it is not enough to be harmful.

“The amount of radiation that you’re exposed to during a routine screening mammography is extremely low and will almost certainly not result in any kind of cancer down the road in your life,” says Dontchos.

Regular breast cancer screening is important, whatever your risk

Whether you are at high risk or average risk, screening tests for breast cancer are important for women to have on a regular basis.  

Dontchos recommends that all women, regardless of perceived risk, work with their primary care provider to assess their breast cancer risk by age 25, so they have a plan in place.

When it comes to breast cancer, knowing your risk and following the current recommendations for screenings means you can find any cancer early when it is more treatable, so that you can live a long, healthy life.