Comparing Breast Cancer Screening Guidelines to Maximize Breast Cancer Mortality Reduction and Increase Life-Years Gained
The goal of breast cancer screening is to decrease breast cancer mortality and increase life-years gained. Consistent screening for breast cancer can reduce breast cancer deaths by 40%. Everyone agrees that breast cancer screening decreases mortality, however, there continues to be several varying recommendations. Most of the recommendations fall under 1 of 2 guidelines, one supported by The United States Preventive Services Task Force (USPSTF), and the second supported by The National Comprehensive Cancer Network (NCCN), The American College of Radiology (ACR), The College of Obstetrics and Gynecology (ACOG), and The Society of Breast Imaging (SBI).
USPSTF is responsible for providing recommendations for all cancer screening examinations, including breast cancer screening. The task force provides their recommendation in a grading system based on their internal review of the literature and issues/concerns related to the screening examination. They also rely on modeling estimates from the Cancer Intervention and Surveillance Modeling Network (CISNET) when formulating recommendations. Insurance coverage for screening examinations is often tied to the USPSTF recommendations.
The ACR, ACOG, and SBI are professional medical organizations representing health care providers who specialize in breast health care. The NCCN is a not-for-profit alliance of 33 leading cancer centers devoted to patient care, research, and education.
In 2009 and 2016, the USPSTF recommended breast cancer screening for women age 50-74 biennially (every 2 years). These recommendations did not align with the recommendation of annual screening beginning at age 40 supported by ACR, ACOG, SBI, and NCCN.
In 2023, the USPSTF issued new draft recommendations for breast cancer screening of women at average risk to begin at age 40, but screen biennially. Moving the recommended screening age to begin at 40 is a huge step in the right direction to decrease breast cancer mortality when it is known that:
- 1 in 6 breast cancers are in women aged 40-49
- 25% of women who die from breast cancer are diagnosed in their 40’s, per the American Cancer Society
- Women in their 40’s tend to develop more aggressive cancers with a worse prognosis
Although adjusting the screening age from 50 to 40 is a big step in the right direction, the biennial screening recommendation is still not in line with the recommendation supported by the societies that represent breast health experts. To further explain why ANNUAL screening beginning at age 40 is still consistently recommended by breast health experts vs biennial screening, looking at the CISNET modeling results which was reported in the paper by Monticiollo, et al (Radiology: Volume 310: Number 2—February 2024) is enlightening.
There are 3 categories of screening recommendations to consider with the CISNET modeling:
- 50-74 years biennally (USPSTF 2009 and 2016 recommendations)
- 40-74 years biennally (USPSTF 2023 draft recommendations)
- 40-79* years annually (ACR, SBI, ACOG, and NCCN recommendations).
*Note – there is no consensus on the age that screening should stop. However, 40-79 best approximates the recommended age range for screening from these organizations.
Mortality reduction is the first important factor to consider. Using the CISNET 2023 modeling data for 3D tomosynthesis screening examinations (the most advanced screening modality currently available), breast cancer mortality reduction is as follows:
- Biennial, ages 50-74 years – 25.4%
- Biennial, ages 40-74 years – 30%
- Annual, ages 40-79 years – 41.7%
Comparing the 2009 and 2016 USPSTF recommendations to the 2023 draft recommendations, there is an 18% relative improvement in mortality reduction, which is a step in the right direction. However, there is a 64% relative improvement over the 2009/2016 recommendations when screening ANNUALLY for 40-79 year old women, which is more than the 39% relative improvement seen with the 2023 draft recommendations.
The second data point evaluated is number of breast cancer deaths averted per 1000 women screened:
- Biennial, ages 50-74 years – 6.7
- Biennial, ages 40-74 years – 8.2
- Annual, ages 40-79 years – 11.5
The number of breast cancer deaths averted per 1000 women screened is highest for women age 40-79 screening annually at 11.5. This is 40% higher than biennial screening ages 40-74 and 72% higher than biennial screening ages 50-74.
The third data point evaluated is number of life-years gained per 1000 women screened:
- Biennial, ages 50-74 years – 121
- Biennial, ages 40-74 years – 165
- Annual, ages 40-79 years – 230
The number of life-years gained per 1000 women screened is also highest in women aged 40-79 screening annually at 230. This is 39% higher than with biennial screening ages 40-74 and 90% higher than with biennial screening ages 50-74.
Per the CISNET modeling data, the recent USPSTF draft recommendations to screen biennially beginning at age 40 will lead to decreased breast cancer mortality and increased life-years gained compared to their 2009 and 2016 recommendations. However, the 2023 USPSTF recommendations still fall short of the breast health expert societies recommendations of annual screening beginning at age 40 where modeling shows the largest benefit of decreased breast cancer mortality and increase in life-years gained.
Written by Danielle Carroll, M.D.
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