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

The US Preventive Services Task Force (USPSTF) has published a systemic review that determines that biennial screening mammography for women aged 40 to 74 has moderate net benefits, updating its previous recommendation that mammography begin at age 50 .¹

Breast cancer rates in people assigned female at birth between the ages of 40 and 49 have increased steadily, especially from 2015 to 2019 (2% annual increase). This includes cisgender women, transgender men, and non-binary 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 tumor characteristics compared with DBT screening or digital mammography.

Although there is debate about the frequency of screening (every two years or 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 data from the Behavioral Risk Factor Surveillance System (BRFSS) to analyze social determinants of health and health-related social needs in relation to mammography use. A major barrier to mammography use was life dissatisfaction, with social isolation, unemployment, and financial obstacles being linked to lower motivation to make an appointment for a mammogram.²

Race is also a factor in breast cancer outcomes, with black women facing a 40 percent higher death rate from breast cancer, according to the USPSTF recommendation statement.¹ The National Institute on Minority Health and Disparities recognizes this disparity and its causes, including access to health care, social factors and genetics.

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

The incidence of breast cancer is twice as high among black patients as among white patients. According to 2020 data, black patients have a similar or higher rate of self-reported mammograms compared to all women (84% vs 78%, respectively). Screening tests are essential for the diagnosis of breast cancer, so any delay or inadequacy in the diagnostic process can lead to negative results compared to receiving prompt and effective care.

Endocrine therapy helps prevent cancer return in hormone-positive patients, but adherence is a challenge. Black patients are more likely to discontinue treatment compared with white patients, in part because of a greater burden of physical and psychological symptoms, the recommendation statement continued.

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

The 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 detection.

According to the American Cancer Society, false positives on mammograms are more common in women who are younger, have dense breasts, have a family history of cancer, or those who take estrogen. Half of the female population will experience a false positive within 10 years, but prior comparison mammograms cut this risk in half.³

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

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

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

There were no identifiable strategies to test the comparative effectiveness of different ages for starting or stopping screening. One study suggested continuing screening between ages 70 and 74 because there was a 22% decreased risk of breast cancer mortality compared to stopping screening at age 70.

If screening begins at age 40 and continues through age 79, about 0.8 breast cancer deaths per 1,000 women screened would be prevented. It is estimated that 1.3 additional breast cancer deaths would be prevented by screening biennially between ages 50 and 74 for every 1,000 women screened over a lifetime of screening all women. Biennial screening starting at age 40 would result in 1.8 breast cancer deaths averted per 1,000 women for the black patient population.

Modeling data estimated that biannual screening between ages 40 and 74 would result in 1,376 false positives per 1,000 women over a lifetime. This biennial screening strategy was estimated to lead to 14 cases of breast cancer being overdiagnosed per 1,000 people screened over the lifetime of screening.

An 8-year study showed that continued annual mammograms after age 70 resulted in more cancer detections compared to stopping. This resulted in fewer missed cancers and potentially less follow-up and treatment. Deaths from breast cancer were similar in the 75- to 84-year-old group, likely due to other health problems.

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

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

References

1. US Preventive Services Task Force. Breast cancer screening: Recommendation statement from the US Preventive Services Task Force. JAMA. 2024;1-13. doi:10.1001/jama.2024.5534

2. Santoro C. Mammography use linked to social determinants, revealing the 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 mammography | 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 % 20 more