When should you get a mammogram? Conflicting advice makes it hard to know

WASHINGTON– Deciding when to have routine mammograms is confusing. Some health groups recommend women start at age 40 or 45, while another recently opted for age 50. They also differ on whether annually or every two years is best.

These conflicting opinions are at least partly due to the fact that breast cancer screening guidelines are designed for women who are at average risk and have no possible symptoms of cancer. But breast cancer is so common that it’s difficult to know who is truly “average” and how to weigh the pros and cons of screening.

“Breast cancer is not a single disease,” said Dr. Laura Esserman of the University of California, San Francisco. “So how on earth does it make sense to screen everyone the same way when not everyone is at the same risk? »

Esserman is leading research to better understand the nuances of who is at low or high risk or somewhere in between and potentially offer more tailored screening advice.

In the United States, more than 320,000 women will be diagnosed with breast cancer this year, according to the American Cancer Society. Mortality rates have been falling for decades, largely due to better treatments. But it remains the second leading cause of cancer death among American women – and diagnoses are increasing.

For now, here are a few things to know.

The most recent guidelines come from the American College of Physicians, which recommends average-risk women ages 50 to 74 get a mammogram every two years. For those ages 40 to 49, the guidelines recommend discussing the pros and cons with a doctor and, if they choose screening, going every two years.

This notice, published last month, came as a surprise. Most other U.S. health groups have urged women to start earlier, around midlife. The influential U.S. Preventive Services Task Force recently changed its guidelines to start mammograms every two years at age 40 instead of 50.

The American Cancer Society has long recommended annual mammograms for women ages 45 to 54, but says they can choose to start at age 40. For those aged 55 and older, the Cancer Society says women can upgrade to every two years or choose to continue for annual checkups.

The new guidelines from the American College of Physicians also say doctors can ask if women 75 or older want to stop routine screening. On the other hand, the Cancer Society says there is no reason to stop if you are still healthy.

The more likely a woman is to develop breast cancer, the more she will benefit from more frequent screenings. But beyond certain well-known factors such as the BRCA1 or BRCA2 genes responsible for cancer, it is difficult for women to know their true risk. Age has long been a predictor, as the risk of breast cancer increases as women age.

Mammograms are not perfect. Sometimes they miss the cancer or an aggressive tumor appears after a routine mammogram. But the guidelines seek to balance the benefits of early cancer detection with possible harms, such as the stress and pain of investigating suspicious areas that don’t turn out to be cancerous.

“We’re not saying there’s no benefit from mammograms in the 1940s,” cautioned Dr. Carolyn Crandall of the University of California, Los Angeles, who chaired the American College of Physicians report. But “there’s a closer balance between the benefits you might get and the harms among 40- to 49-year-olds.”

The American Cancer Society recommends starting annual mammograms at age 45 because it found that the incidence of breast cancer among 45- to 49-year-olds was higher than in their early 40s — closer to that of 50- to 54-year-olds, said public health researcher Robert Smith, the society’s expert on early cancer detection.

What’s missing is a way to know whether a person is more likely to develop aggressive breast cancer or a slow-growing cancer, Smith noted.

Nearly half of women over 40 have dense breast tissue, which can make it more difficult to detect a tumor on a mammogram and slightly increase the risk of developing cancer.

After a mammogram, women are informed of their breast density. Many experts say it’s not yet clear whether women with dense breasts would benefit from adding ultrasounds or MRIs to their screening. But new guidelines from the American College of Physicians advise considering 3D mammography — what doctors call digital breast tomosynthesis, or DBT.

In the future, adding genetic testing – which looks at more than just the well-known BRCA genes – as well as broader risk factors could help refine women’s optimal mammogram schedule.

A recent study of nearly 46,000 women, called the WISDOM trial, used age, genetic testing, lifestyle, medical history and breast density to classify women as low, medium, high or high risk. This level of risk determined whether they waited to start mammograms until age 50, whether they went every two years, or every year — and the highest risk group had to get screened twice a year, once with a mammogram and again with an MRI. Risk-based analyzes were compared to standard annual mammograms.

Risk-based screening worked as did annual screening, Esserman’s team reported in the medical journal JAMA. One surprise: About 30 percent of women whose genetic tests indicated an increased risk did not report relatives with breast cancer. While more research is underway, Esserman hopes the initial results will soon begin to influence guidelines.

AI tools are also in the works to assess a woman’s risk of developing breast cancer in the coming years based on clues in her mammogram, another possible way to identify who might benefit from more or less frequent screening.

For now, women can talk with their doctor about close relatives who have had cancer, their own general health and other risk factors, such as whether and at what age they had children.

Regardless of the age and mammogram interval you choose, the best advice is to stick to it, said the cancer society’s Smith: “Breast cancer screening works best when done regularly.” »

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