New research suggests that women with certain risk factors should begin screenings at age 30, but experts say mammography may not be effective for women in this age group.

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. A study showed that annual mammography beginning at 30 may benefit women who have dense breasts or a family or personal history of breast cancer.

Mammography is the standard approach used to screen for breast cancer. Women at average risk for breast cancer should get yearly mammograms starting at age 45, then every other year starting at age 55, but some women could choose to have mammograms as early as 40. Recommendations for younger women aren’t as clear, but women at risk for breast cancer require earlier onset or supplemental screening. 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.

In 2018, the American College of Radiology started to recommend that all women be assessed for breast cancer risk when they reach 30 including a baseline screening mammogram at age 30 to determine breast density.

Though much research has been done on the 40 to 49 age group, it is difficult to study women in the 30 to 39 age range, as most in this age group don’t get mammograms, yet they are at risk for breast cancer. More than 1,000 women under age 40 die every year from breast cancer in the United States. About 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.

What the study found: In this latest study, 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 were evaluated.

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.

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. 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. 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.

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.

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.

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.

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. In women with a family history of breast cancer, screening is often started 10 years before the youngest relative was diagnosed, but in younger women don’t only rely on mammography. Patients with increased risk due to genetics or the BRCA gene should start screening earlier and use other scans, like an MRI or ultrasound device, in addition to mammography.

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.

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.