woman lymph armpit examination. Node-Positive Breast Cancer
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The U.S. Preventive Services Task Force (USPSTF) has updated its breast cancer screening recommendations to include biennial screening mammography for all women aged 40–49 years, rather than individualizing the screening decision for women in this age group.

The statement, published in JAMA, updates the 2016 recommendation for biennial screening mammography among women aged 50–74 years plus personalized decision-making, based on factors such as individual risk and personal preferences, for women aged 40–49 years.

The USPSTF also updated the recommended primary screening modalities to reflect advances in technology and include digital breast tomosynthesis (DBT), a three-dimensional technique that includes evaluation of two-dimensional images, generated either with digital mammography or using a DBT scan to produce a synthetic digital mammography image.

Breast cancer is the second most common cancer diagnosed among U.S. women and the second most common cause of cancer death. In 2023, an estimated 43,170 women died of breast cancer. Non-Hispanic White women have the highest incidence of breast cancer and non-Hispanic Black women have the highest mortality rate.

The USPSTF commissioned a systematic review to evaluate how different mammography-based breast cancer screening strategies impact the incidence of and progression to advanced breast cancer, breast cancer morbidity, and breast cancer–specific or all-cause mortality.

Modeling data estimated that compared with biennial screening from ages 50–74 years, biennial screening from ages 40–74 years would lead to 1.3 additional breast cancer deaths averted (median 6.7 vs 8.2 deaths averted) per 1000 women screened over a lifetime.

These models also estimated that screening benefits in terms of breast cancer deaths averted were greater for Black women relative to all women. Specifically, biennial screening starting at age 40 years would result in 1.8 additional breast cancer deaths averted per 1000 Black women screened compared with starting screening at 50 years of age (median 9.2 vs 10.7 deaths averted) per 1000 women screened.

The authors of the recommendation statement point out that breast cancer incidence increased gradually among women aged 40–49 years between 2000 and 2015 but then grew more sharply, with a two percent increase per year observed between 2015–2019.

Together, these factors led the USPSTF to conclude that screening mammography in women aged 40–49 years has moderate net benefit (classed as a Grade B recommendation) in reducing the number of breast cancer deaths.

The recommendation to begin screening at age 40 years applies to cisgender women and all other people assigned female at birth (including transgender men and nonbinary individuals) at average risk for breast cancer as well as those who have factors associated with an increased breast cancer risk, such as a family history of breast cancer) or having dense breasts.

The recommendations do not, however, apply to people who have a genetic marker or syndrome associated with a high breast cancer risk (eg, BRCA1 or BRCA2 genetic variations), a history of high-dose radiation therapy to the chest at a young age, or previous breast cancer or a high-risk breast lesion on previous biopsies. There are separate guidelines for these individuals.

For women with dense breasts, the task force found insufficient evidence to assess the balance of benefits and harms of supplemental breast cancer screening using breast ultrasonography or magnetic resonance imaging when considering an otherwise negative screening mammogram.

Commenting on this finding, Joann Elmore, MD, David Geffen School of Medicine at UCLA, and Christoph Lee, MD, University of Washington School of Medicine, say that “[t]here is an urgent need for better evidence on the topic of supplemental screening with ultrasound or MRI for women with dense breasts.”

They note that the matter “is of critical concern” because from September 2024 the U.S. Food and Drug Administration will mandate that all U.S. screening facilities inform women about their breast density with their mammography results. Some states will require a statement recommending that women discuss the option of supplemental screening ultrasound or MRI due to dense breasts with their primary care clinicians.

The USPSTF also found insufficient evidence to determine the balance of benefits and harms of screening mammography in women aged 75 years or older.

The guidelines therefore state that “[c]linicians should use their clinical judgment regarding whether to screen for breast cancer in women 75 years or older and regarding whether to use supplemental screening in women who have dense breasts and an otherwise normal mammogram.”

Elmore and Lee say that while the task force highlights the need for further research in these two areas, “it overlooks the pressing issue of emerging use of artificial intelligence (AI) support tools for image interpretation.”

They point out that although “AI algorithms show promise for enhancing cancer detection, their impact on patient outcomes and the balance between benefit and harms remain uncertain. Moreover, these AI tools have been primarily trained and tested on older White women, potentially exacerbating existing disparities unless they are validated on diverse populations to ensure that benefits are equitably experienced across all races and ethnicities.”

An editorial by Wendie Berg, MD, PhD, the University of Pittsburgh School of Medicine, in JAMA Oncology, describes the updated recommendations as “an important step forward.” However, she believes the guidelines “stop short” by recommending biennial screening over an annual schedule. “Annual screening is particularly important for premenopausal women, especially women in racial and ethnic minority group,” she suggests.

The recommendations state that, according to the available evidence “biennial screening has a more favorable trade-off of benefits vs harms than annual screening.”

Berg also make the important point that “[t]o benefit from any screening options, women must participate.”

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