Screening mammograms linked to earlier breast cancer detection

Screening mammograms linked to earlier breast cancer detection | Image Credit: © Peakstock - © Peakstock - stock.adobe.com.

Breast cancer is often diagnosed at an earlier stage among women with a history of screening mammography, reducing associated mortality, according to a recent study published in JAMA Network Open.¹

Screening recommendations and evidence gaps

The US Preventive Services Task Force (USPSTF) recommends women aged 40 to 75 years receive biannual screening to improve the odds of early breast cancer detection.² However, the USPSTF has also stated the evidence to recommend screening in women aged over 75 years is currently insufficient.

“Identifying this potential difference in health outcomes based on screening history may facilitate a more accurate evaluation of screening effectiveness,” wrote investigators.¹

Evaluating breast cancer outcomes

The cohort study was conducted to determine the link between screening history and breast cancer outcomes among older US women. Data was obtained from the Surveillance, Epidemiology and End Results-Medicaid linkage between January 1, 2005, and December 30, 2020.

This data included screening history, demographics, biology, cancer diagnosis, and treatment for breast cancer patients. Women aged at least 70 years with estrogen receptor-positive or human epidermal growth factor receptor 2–negative breast cancer determined by screening mammogram were included in the analysis.

Additional eligibility criteria included continuous Medicaid coverage from 5 years before diagnosis through 1 year following diagnosis. Receiving 1 or more screening mammogram within 5 years before diagnosis was defined as the exposure, with patient categories including no vs any screening before diagnosis.

Determining stage at diagnosis

The stage at diagnosis was reported as the primary outcome, classified as either very early or later stage diagnosis. Diagnoses were made based on American Joint Committee on Cancer TNM stages. Demographic, socioeconomic, tumor, and treatment-related covariates were obtained during diagnosis.

There were 13,028 patients included in the analysis, 3.6% of whom were Asian, 4.2% Hispanic, 6.2% non-Hispanic Black, 84.3% non-Hispanic White, and 1.7% other or unknown race and ethnicity. Of women, 38.5% were aged 70 to 74 years and 30.9% were aged 75 to 79 years.

Screening rates and impact

Prior screening was reported in 77.5% of participants overall. Those with at least 1 primary care physician or annual wellness visit, aged 70 to 74 years, and non-dual eligible had increased rates, at 78.1%, 79.1%, and 79.9%, respectively.

Later-stage disease was reported in 29.3% of women at diagnosis, with a rate of 25.1% among women with prior screening. Among those without prior screening, the prevalence of later-stage diagnosis was 43.4%. This indicated a 54% reduced chance of being diagnosed at a later stage when having prior screening, with an adjusted odds ratio (aOR) of 0.46.

Being dual eligible and living in regions with higher poverty and lower education were also linked to later-stage diagnosis, with aORs of 1.17, 1.21, and 0.83, respectively. In patients with grade 3 or grade 4 tumors vs grade 1 tumors, the aOR for later diagnosis was 4.90.

Mortality reduction and implications

The odds of breast cancer mortality were also significantly reduced among women with prior screening, at a rate of 3.3% vs 8% among women with no prior screening. This indicated an aOR of 0.63 for breast cancer-specific death among this population.

These results indicated earlier stage of diagnosis for breast cancer and reduced mortality among women aged at least 70 years with prior screening mammography. Investigators noted limitations in the data because of residual cofounding.

“Our findings support the potential for routine screening to improve breast cancer outcomes,” investigators concluded.

References

1. Huang S, Westvold SJ, Soulos PR, et al. Screening history, stage at diagnosis, and mortality in screen-detected breast cancer. JAMA Netw Open. 2025;8(4):e255322. doi:10.1001/jamanetworkopen.2025.5322
2. Nicholson WK, Silverstein M, Wong JB, et al; US Preventive Services Task Force.Screening for breast cancer: US Preventive Services Task Force recommendation statement.JAMA. 2024;331(22):1918-1930. doi:10.1001/jama.2024.5534