USPSTF Lowers Age for Biennial Mammograms to 40, Citing Early Detection Benefit

Physician and Patient at Mammography Exam. |Image Credit: LStockStudio - stock.adobe.com

The US Preventive Services Task Force (USPSTF) has released a systemic review determining that biennial mammography screening for women aged 40 to 74 years has moderate net benefits, updating its previous recommendation for mammography to start at age 50.¹

Breast cancer rates in people assigned female at birth aged 40 to 49 years have risen steadily, especially from 2015 to 2019 (2% annual increase). This includes cisgender women, transgender men, and nonbinary individuals.

Commonly used and effective mammography screening devices include digital mammography and digital breast tomosynthesis (DBT or “3D mammography”). There were no statistically significant differences in breast cancer detection or in tumor characteristics when compared with DBT screening or digital mammography.

While debate exists over screening frequency (every other year vs annually), biennial mammograms often offer a better balance of benefit and risk. Treatment decisions are also individualized based on various factors and patient preferences.

A recent study used Behavioral Risk Factor Surveillance System (BRFSS) data to analyze social determinants of health and health-related social needs in relation to mammography use. A large barrier to mammogram use was life dissatisfaction, as social isolation, unemployment, and financial obstacles were linked with lower motivation to make a mammogram appointment.²

Race is also a factor in breast cancer outcomes, as Black women face a 40% higher breast cancer death rate, according to the USPSTF recommendation statement.¹ The National Institute of Minority Health and Disparities recognizes this disparity and its causes, including health care access, social factors, and genetics.

Structural racism, including unequal access to health care and exposure to environmental hazards, contributes to higher breast cancer death rates in Black patients. In addition, residential segregation is prevalent in patients with triple-negative breast cancer and linked to decreased survival rates in Black women.

Breast cancer incidence is twice as high among Black patients compared with White patients. According to data from 2020, Black patients have a similar or higher rate of self-reported mammography screenings compared with all women (84% vs 78%, respectively). Screenings are essential to breast cancer diagnosis, so any delays or inadequacies in the diagnostic process can result in negative outcomes downstream vs receiving prompt, effective care.

Endocrine therapy helps prevent cancer return in hormone-positive patients, but adherence is a challenge. Black patients are more likely to stop treatment compared with White patients, partly due to greater physical and psychological symptom burdens, the recommendation statement continued.

Providing better access to health care, financial assistance, and support services for everyone, especially those at higher risk due to race, rural location, or income, could significantly reduce breast cancer deaths. This includes ensuring equitable follow-up care after screenings and timely, effective treatment.

Potential harms of screening include false positives that could lead to psychological harm, additional testing, invasive follow-up procedures, overdiagnosis, overtreatment, and radiation exposure, but modeling data indicate a more favorable balance of benefits to harms for biennial than annual screening.

According to the American Cancer Society, false positives in mammograms are more common in younger women, those with dense breasts, those with a family history of cancer, or those taking estrogen. Half of the female population will experience a false positive over 10 years, but prior mammograms for comparison halve that risk.³

Previously, the USPSTF suggested biennial mammography screenings for patients between 50 and 74 years old, only advising women aged 40 to 49 years to undergo screening based on individual risk factors, personal preference, or values.¹ Based on evidence from a systemic review the USPSTF commissioned, the task force now recommends biennial mammography screenings for women aged 40 to 74 years.

Modeling studies among 4 teams created race-specific breast cancer models for Black women to incorporate potential benefits or harms of different mammography screening strategies.

In a meta-analysis, screening mammography was associated with lower breast cancer mortality risk across all age groups studied.

There were no identifiable strategies for testing comparative effectiveness of different ages to begin screening or stop screening. One study suggested continued screening between ages 70 and 74 years because there was a 22% decrease in risk of breast cancer mortality compared with halted screening at 70 years.

If screening begins at age 40 and continues throughout age 79, around 0.8 breast cancer deaths would be averted per 1000 women screened. An estimated 1.3 additional breast cancer deaths would be avoided through biennial screening from age 50 to 74 years per 1000 women screened over a lifetime of screening all women. Biennial screening beginning at age 40 years would result in 1.8 breast cancer deaths avoided per 1000 women for the Black patient population.

Modeling data estimated that screening biennially from ages 40 to 74 years would result in 1376 false positives per 1000 women over a lifetime of screening. This strategy of biennial screening was estimated to lead to 14 overdiagnosed cases of breast cancer per 1000 persons screened over a lifetime of screening.

An 8-year study showed continued annual mammograms after age 70 led to more cancer detections compared with stopping. This resulted in fewer missed cancers and potentially less follow-up and treatment. Breast cancer deaths were similar in the group aged 75 to 84 years, likely due to other health concerns.

Dense breast tissue did not affect screening results, but DBT with mammograms doubled radiation exposure compared with mammograms alone.

Based on these results, USPSTF now recommends biennial mammograms for patients aged 40 to 74 years, acknowledging the moderate net benefit for early detection. While disparities exist, particularly for Black women, increasing access to quality health care and addressing social determinants of health are crucial steps toward reducing breast cancer mortality rates for all populations.

References

1. US preventive services task force. Screening for breast cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2024;1-13. doi:10.1001/jama.2024.5534

2. Santoro C. Mammography use linked to social determinants, revealing need to bridge gaps with community support. AJMC. April 9, 2024. Accessed April 30, 2024. https://www.ajmc.com/view/mammography-use-linked-to-social-determinants-revealing-need-to-bridge-gaps-with-community-support

3. Limitations of mammograms | How accurate are mammograms? American Cancer Society. https://www.cancer.org/cancer/types/breast-cancer/screening-tests-and-early-detection/mammograms/limitations-of-mammograms.html#:~:text=False%2Dpositive%20results%20are%20more