A new approach to breast screening suggests that all women should have a baseline assessment of breast density. Mammography At the age of 40.
The results are then used to stratify further screening, starting annually from age 40 for women at average risk of breast congestion and every two years from age 50 for women without breast density. Start screening.
Such an approach is cost-effective and provides a more risk-based, more targeted strategy. Breast cancer Compared to current practice, the author states that it is headed by Dr. Tina Shih of the University of Texas MD Anderson Cancer Center (Houston).
Their modeling research was published online today Annual report of internal medicine.
However, the experts writing in the accompanying editorial have not been persuaded. Karla Kerlikowske, MD and Kirsten Bibbins-Domingo, MD, PhD of the University of California, San Francisco, point out that not all women with dense breasts are at increased risk of breast cancer. They warn against relying solely on breast cancer when deciding on a screening strategy, and state that age and other risk factors should also be considered.
Proposed new approach
Current recommendations from the United States Preventive Services Task Force (USPSTF) suggest that women in their 40s may choose to undergo mammography screening based on their personal preferences. Medscape Medical News.
However, these recommendations do not take into account the additional risk that breast cancer poses to breast cancer risk. The only way a woman knows breast cancer is to get a mammogram. “If you obey [current] The guidelines do not give you the density of your breasts until you are 45 or 50 years old, “she commented.
“But what if you knew about breast cancer before and acted on it-will it make a difference?” This was the question her team tried to explore.
In their study, the authors identified women with dense breasts in Category C (unevenly dense breasts) and Category D (very dense breasts) of the Breast Imaging and Data System (BI-RADS). Defined as a woman.
The team used a computer model to compare seven different breast screening strategies.
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No screening
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Mammography every 3 years from 50 to 75 years old (T50)
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Biennial mammography from 50 to 75 years (B50)
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Stratified mammography from 50 to 75 years for women with dense breasts at age 50, screening every 3 years from 50 to 75 years for women without breast density at age 50 (SA50T50)
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Stratified mammography from 50 to 75 years for women with dense breasts at age 50, biennial screening from 50 to 75 years for women without breast density at age 50 (SA50B50)
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Stratified mammography from 40 to 75 years for women with dense breasts at age 49, screening every 3 years from 50 to 75 years for women without breast density at age 40 (SA40T50)
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Stratified mammography from 40 to 75 years for women with dense breasts at age 40, biennial mammography (SA40B50) for women from 50 to 75 years with no dense breasts at age 40
Compared to the unscreened strategy, the average number of women’s lifetime mammography sessions increased from 7 mammography per lifetime for the least frequent screening (T50) to 22 mammography per lifetime for the most intensive screening schedule, the team said. Will report.
Compared to no screening, screening reduces breast cancer deaths from 8.6 per 1000 women (T50) to 13.2 per 1000 women (SA40B50).
Cost-effectiveness analysis shows that the proposed new approach (SA40B50) resulted in an incremental cost-effectiveness ratio of $ 36,200 per quality-adjusted life year (QALY) compared to the currently recommended biennial screening strategy. I did. The author points out that this is within the socially accepted threshold of $ 100,000 per QALY.
On the other hand, false positive results and overdiagnosis will increase, the authors say.
The average number of false positives increases from 141.2 per 1000 women who received the least frequent 3-year mammography screening schedule (T50) to 567.3 per 1000 women with the new approach (SA40B50).
They also add that the rate of overdiagnosis also increases from a low of 12.5% ​​to a high of 18.6%.
“This study does not say that everyone needs to start screening at age 40, but at age 40, baseline mammography is done to understand the status of breast cancer, and then screening is based on: You can change the schedule. Personal risk. “
“Compared to the other screening strategies considered in our study, this strategy is associated with the greatest reduction in breast cancer mortality and is cost effective. [although it] It contains the most screening mammograms in a woman’s life and has a high rate of false positive results and overdiagnosis, “the authors conclude.
The underlying problem with this approach
The underlying problem with this approach of stratifying risks in measuring breast density is that not all women with dense breasts are at increased risk of breast cancer based on a single measurement. , The editor commented.
In fact, only about a quarter of women with dense breasts are at increased risk of missing invasive cancer within a year of being mammogram-negative, Kerlikowske and Bibbins-Domingo point out. These women Breast Cancer Surveillance Consortium Risk model.
“This observation means that most women with dense breasts can be screened every other year without having to consider annual screening or supplemental diagnostic imaging,” the editor writes. I am.
“Therefore, care should be taken to use breast cancer alone to determine if a woman is at increased risk of breast cancer,” they emphasize.
The alternative option is to focus on the overall risk in choosing a screening strategy, they suggest. For example, most guidelines recommend screening between the ages of 50 and 74. Therefore, identifying women in their 40s who are at the same risk as women aged 50-59 is one way to determine who will benefit from starting screening early, the editors said. I will.
“Therefore, first-degree women with a history of breast cancer or breast biopsy may be offered screening in their 40s, and up to their 40s if mammography shows that the breasts are dense. You can continue screening every other year, “said the editor. “Such women with non-dense breasts can resume biennial screening at age 50.”
Sea said Medscape Medical News She disagreed with the editor’s suggestion that physicians could focus on overall breast cancer risk to select the appropriate screening strategy for an individual patient.
“We suggest that you do a baseline assessment at age 40 to know the density of your breasts, rather than waiting for a woman to get older,” she said.
“But what the editors are proposing is a more cost-effective strategy,” she admitted. Shih also estimates that only one-quarter of women with dense breasts are actually at increased risk of breast cancer, according to Kerlikowske and Bibbins-Domingo’s estimates that breast cancer is in the BI-RAD category “D”. It may reflect that it is restricted to women only. ..
However, as Shih points out, women with both Category C and Category D breast densities are at increased risk of breast cancer, so ignoring women with low breast densities is at higher than average risk. I can’t deal with the fact that it’s expensive. For breast cancer.
“As we learn more and more about breast cancer, it’s getting harder and harder for universal screening strategies to work, so people are starting to talk about screening strategies based on patient risk classification,” Shih said. I did.
“It would be difficult to implement this kind of strategy, but it seems like the right path,” she added.
This study was funded by the National Cancer Institute. Shih reports grants from the National Cancer Institute during the course of the study and personal fees from Pfizer and AstraZeneca other than the submitted studies. Kerlikowske is GRAIL’s unpaid consultant for STRIVE research. Bibins-Domingo does not disclose the relevant financial relationship.
Anne Internal Medicine. Published online on February 8, 2021.
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