Breast Cancer Screening Should Be Based on Each Patient’s Individual Risk Level

In a risk-stratified breast screening approach, the age at which a woman is screened for breast cancer (BC) should be based on her individual risk level, according to the authors of a study published in ACS Journals. However, the frequency of screenings may not need to be based on risk level.

“The absolute risk of breast cancer, dependent on age and polygenic risk score (PRS) alone or combined with other risk factors, is associated with the early onset of preclinical screen-detectable breast cancer,” wrote study authors. “However, it is not associated with the risk of progression from preclinical screen-detectable to symptomatic clinical cancer.”

Despite the effectiveness of screening for BC, it can lead to overdiagnosis, overtreatment, patient stress, and increased health care burden. Further, current screening standards only consider age to be a risk factor, which is why more people support a risk-stratified screening approach, which considers a range of risk factors.

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The natural history of BC can also impact screening intervals and effectiveness. Natural history considers sojourn time (the amount of time a tumor is asymptomatic but detectable during as creening), which can help in gauging the optimal interval between screens, screening effectiveness in relation to cancer death, and degree of overdiagnosis. However, investigators still do not know if BC risk is connected to natural history, and if this can influence screening outcomes.

In the Studies of Epidemiology and Risk Factors in Cancer Heredity study, investigators used individualized risk predictions (based on PRS) alone and combined with other risk factors to understand if sojourn time differed between risk groups.

The results showed that women with a high risk of BC had screen-detectable cancer at an earlier age than patients with low risk, however the sojourn time was not significantly shorter.

Investigators also discovered that the type of cancer affected sojourn time. BC with an ER–, PR–, and HER2+ subtype are more aggressive, meaning that the sojourn time is shorter.

Investigators suggest that risk-stratification programs should be designed to account for women with high risk—since they tend to be younger, the program should account for age based on risk factor to improve early detection and prevent symptomatic disease progression.

Generally, sojourn time did not have a large variation based on risk group. “That is, higher risk is not associated with faster progression or more aggressive disease,” study authors wrote.

The authors noted that limitations of the study included the cohort consisting of more women who had cancer than did not and the cohort was predominantly women from East England with European ancestry, limiting generalizability. Additionally, the investigators noted that a limitation also exists in the assumption that screening-detectable cancers will become symptomatic, as well as potential survival bias.

The authors also noted that more research on how risk-stratification is organized and implemented would be beneficial.

“Further studies are needed to identify the optimal risk-stratified screening strategies that could improve the benefit-to-harm, and the cost-effectiveness, ensure the acceptability, and promote equitable access to risk-stratified breast screening program,” investigators wrote.

REFERENCE

Bhatt R, van den Hout A, Antoniou AC, et al. Estimation of age of onset and progression of breast cancer by absolute risk dependent on polygenic risk score and other risk factors. ACS. 2024. doi:10.1002/cncr.35183