A new study suggests mammograms beginning at age 30 may be appropriate for women with certain risk factors, but experts say the screening method may not be effective for this group.
The study that was presented today at the annual meeting of the Radiological Society of North America found that annual mammography beginning at 30 may benefit women who have dense breasts or a family or personal history of breast cancer.
The researchers analyzed data from more than 5 million mammograms performed on more than 2.6 million women between 2008 and 2015 in 150 facilities spanning 31 states across the United States.
Mammography is the standard approach used to screen for breast cancer. The American Cancer Society recommends women at average risk for breast cancer should get yearly mammograms starting at age 45, then every other year starting at age 55.
The society also suggests women could choose to have mammograms as early as 40.
Other organizations, including the Radiological Society of North America, recommend annual mammograms at age 40, but the recommendations for younger women aren’t as clear.
“There isn’t enough published data on this topic, but most organizations recognize women at risk for breast cancer require earlier onset or supplemental screening.
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“Our findings suggest that recommendations of screening mammography should be personalized on the basis of a woman’s age, breast density, personal history of breast cancer, and family history of breast cancer,” Dr. Cindy Lee, author of the study and assistant professor of radiology at the NYU Langone Medical Center, told Healthline.
Lee points out that in 2018, the American College of Radiology started to recommend that all women be assessed for breast cancer risk when they reach 30.
“Our findings raise the question whether this baseline risk assessment should include a baseline screening mammogram at age 30 to determine breast density for practices who routinely recommend screening for women in their 40s,” she said. “Future research is needed to evaluate the risks and benefits of performing baseline mammography at age 30.”
Though much research has been done on the 40 to 49 age group, Lee says it’s been difficult to study women in the 30 to 39 age range, as most in this age group don’t get mammograms. But that doesn’t mean they aren’t at risk for breast cancer.
More than 1,000 women under age 40 die every year from breast cancer in the United States.
“Most women diagnosed with breast cancer are 40 years old or older. However, per the most recent statistics by the American Cancer Society, 4 percent of breast cancers will be diagnosed in women younger than age 40. With over 250,000 new diagnoses of breast cancer each year, that is not an insignificant number of women,” Dr. Lauren Nye, an oncologist at the University of Kansas Cancer Center, told Healthline.
What the study found
In this latest study, Lee and colleagues evaluated three specific risk factors: a family history (considered a first-degree relative diagnosed with breast cancer, regardless of age), a personal history of breast cancer, or dense breasts.
“Dense breasts can obscure the underlying mammographic abnormalities, including breast cancers. Having more fibroglandular breast tissue (and less fat) is also itself associated with increased breast cancer risk,” Lee told Healthline.
But experts not associated with the study have advised caution when considering mammography at age 30, particularly on the basis of dense breasts.
Dense breasts are common in younger women. Research estimates 74 percent of women ages 40 to 49 have dense breasts compared with just 36 percent of women in their 70s. Most women aged under 40 have dense breast tissue.
Breast density in mammography refers to the amount of parenchymal tissue relative to the amount of fatty tissue in a breast. Parenchymal tissue looks white on mammography — and so are cancerous masses. Cancers can therefore be harder to detect in those with dense breasts.
Diana Miglioretti, PhD, a professor of biostatistics at the UC Davis School of Medicine, says that given most women in their 30s have dense breast tissue, the benefits of mammography for women without a personal history of breast cancer may not outweigh the risks.
“Women with dense breasts are more likely to have false alarms and benign biopsies from screening mammography. Screening women in their 30s with dense breasts will likely lead to many false alarms and benign biopsies without much benefit, due to the very low rate of cancer in this age group,” she told Healthline.
Miglioretti points out that under current guidelines, “all women with a personal history of breast cancer should be screened annually (unless they have double mastectomy), regardless of age.”
“In addition, women with a risk factor that puts them at very high risk, for example, women with a genetic mutation or prior chest radiation for cancer treatment, should start screening at a younger age,” she said.
“For other women, even women with a family history or dense breasts, the benefits of screening mammography in the 30s are unlikely to outweigh the harms from screening in this age group, given breast cancer is so rare in this age group,” Miglioretti added.
What to ask your doctor about starting mammogram screening
Dr. Onalisa Winblad, a radiologist at the University of Kansas Cancer Center, says other forms of assessment may be helpful for women under 40.
“By the time a woman is 30, she should meet with her doctor and have a discussion about breast cancer risk to assess whether early or additional breast cancer screening may be indicated. Clinical breast exam by a trained medical professional may begin at age 20 as well,” she said.
At this time, no country or organization has guidelines recommending mammography for women under 40, except in the case of having a personal history of breast cancer or other risk factors that would put them at very high risk.
“Mammography simply does not work well in younger women, primarily due to the density of the breast tissue,” Dr. Deanna Attai, an assistant clinical professor at the UCLA David Geffen School of Medicine, told Healthline. “In women with a family history of breast cancer, we often start screening 10 years before the youngest relative was diagnosed, but in younger women don’t only rely on mammography.”
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Attai says for patients with increased risk due to genetics or the BRCA gene, they’ll start screening earlier and often use other scans, like an MRI or ultrasound device, in addition to mammography.
She recommends that women who are concerned about their breast cancer risk should speak with their physician and conduct their own breast exams regularly.
“It is prudent for women to practice breast self-awareness. Understand how your normal breast tissue feels and the monthly variations, check periodically, and report any changes to your physician,” Attai said.
“In addition, know the risk factors and your family history of breast and other cancers, and discuss this with your physician. Women at high risk may be recommended to undergo mammogram or other screening tests such as ultrasound or MRI,” she said.
The bottom line
A recent study suggests mammography beginning at age 30 may be beneficial for women with a personal history of breast cancer, a family history, or dense breasts.
But experts say mammography may not be effective for women in this age group, and other assessments would be more beneficial. Women concerned about their risk for breast cancer should consult their doctor.