The debate over when women should start breast screenings

She said CISNET has limits because only some data is released, so researchers are still lacking a full picture of how long screening should continue. Because the USPSTF only asked CISNET modelers to look at patients screened up to age 79, that is where the data stops. She said there is a question if screening is necessary beyond age 79, but they need more data to make decisions.

"We screen women over the age of 79 all the time. So there are data for women in their eighties, for example, but they're not published and so we don't have access to it. We'd like that access, but we have to work with the limitations that we have," Monticciolo said.

Study findings show less mortality when screening starts earlier

Monticciolo's study, leveraging CISNET models, evaluated the outcomes of different screening schedules. Key findings include:

   • Annual screening from age 40: This approach yields a 42% reduction in breast cancer mortality compared to a 25% reduction with the current USPSTF recommendation of biennial screenings from 50 to 74.
   • Biennial screening from age 40: This schedule results in a 30% reduction in mortality, an improvement over the previous 25% reduction.
   • Annual screening from 40 to 74: A shift to annual screenings in this age range increases mortality reduction to 37%.
   
Monticciolo emphasizes the benefits of starting screenings earlier and conducting them more frequently. She argues that the risks, such as recalls and benign biopsies, are relatively minor compared to the potential to detect and treat cancer early. 

Risks and benefits or earlier and more frequent breast screenings

The debate often centers on the balance between the benefits of early cancer detection and the risks associated with screening. The primary risks involve being recalled for additional imaging or undergoing a benign biopsy. However, Monticciolo points out that these risks are non-lethal and manageable.

From a woman's perspective, the chance of being recalled annually starting at age 40 is about 6.5%, and the likelihood of a benign biopsy is less than 1%. That figure is reduced to 0.88 using tomosynthesis (3D mammography) and screening annually. 

These figures suggest that the risks are minimal, especially when weighed against the potential lifesaving benefits of early detection.

The study also did an analysis of how this looks from the woman's perspective. She said this is really important, because if a woman that's going for a mammogram, she's thinking, how is this going to affect me? The patients want to know the chances they will be recalled for additional imaging or get a biopsy, and their chances of having a benign biopsy.

"I think doctors want to answer that question for their patients as well. So we looked at the exact same data, but looked at it from the woman's perspective. And when you do that, you will find that annual screening starting at age 40, extending to age 79, actually has the lowest risk of recall on a per exam basis,"

She said that is very, very low. In fact, all the scenarios using the 2023 digital breast tomosynthesis data, the risk of getting a biopsy was 1.25 or less, and the risk of recall was less than 9%. She said this is a reason why many centers are moving toward a wider use of digital breast tomosynthesis (DBT) imaging systems.

Special breast screening considerations for younger women and high-risk groups

Monticciolo also highlights the need for risk assessment, particularly for women under 40 who might be at higher risk. Factors such as family history, breast density, and ethnicity (especially among Black women) can influence the risk of developing breast cancer at a younger age. She advocates for risk assessment by age 25 to identify high-risk individuals who may benefit from earlier screening.

"We really are trying to make women more aware of the need for risk assessment because the prevalence is low for women in their twenties. And then it starts going up in the thirties. Not high enough to recommend general screening for everyone at that age, but for black women in particular and women of color, they're getting tumors at younger ages. And so waiting until 50 was an absolute, it was a bad idea for all women, but it was a disaster for women of color," Monticciolo explained.

The ongoing debate over when to start breast cancer screenings reflects the complexities of balancing benefits and risks. Monticciolo's research supports the notion that annual screenings beginning at age 40 provide significant mortality reduction and manageable risks, offering a compelling case for updating current screening guidelines. As more data and advanced modeling techniques become available, these recommendations may continue to evolve, aiming to optimize outcomes for women across diverse populations.

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