When Should You Start Breast Cancer Screening?
The 2024 USPSTF guideline recommends all women at average risk begin biennial screening mammography at age 40, a significant change from the previous recommendation of age 50. Women at high risk should begin earlier with enhanced protocols. All women should have a clinical risk assessment by age 25 to determine their screening strategy.
The USPSTF's 2024 update to start screening at 40 was driven by rising breast cancer incidence in women under 50 and modeling studies showing the mortality benefit of earlier screening. The task force estimated that biennial screening from 40-74 prevents approximately 1.3 additional deaths per 1,000 women screened compared to starting at 50. This brings the USPSTF closer to alignment with the American College of Radiology (ACR), which has recommended annual screening from age 40 since 2010.
High-risk women — defined as those with lifetime breast cancer risk of 20% or greater — should begin screening at age 25-30, typically with both annual mammography and annual breast MRI. High-risk categories include BRCA1/2 mutation carriers, women who received chest radiation between ages 10-30 (e.g., for Hodgkin lymphoma), Li-Fraumeni syndrome, and women with strong family history. Risk assessment using validated models (Tyrer-Cuzick, BRCAPRO) should be performed by age 25 to identify high-risk women early.
The 2024 USPSTF update was driven by rising breast cancer incidence in women under 50
What Types of Breast Cancer Screening Are Available?
Screening methods include 2D digital mammography, 3D mammography (tomosynthesis), breast MRI, breast ultrasound, and clinical breast examination. 3D mammography improves cancer detection by 20-40% compared to 2D alone and reduces callback rates. Breast MRI is reserved for high-risk women due to its high sensitivity but lower specificity.
Digital breast tomosynthesis (3D mammography) has become the standard of care, detecting 20-40% more invasive cancers compared to conventional 2D mammography while reducing false-positive callbacks by 15-40%. During tomosynthesis, the X-ray tube moves in an arc over the breast, creating thin-slice images that can be reconstructed into a 3D representation. This is particularly beneficial for women with dense breast tissue, where overlapping tissue can obscure cancers on 2D imaging.
Supplemental screening for women with dense breasts is an evolving area. The DENSE trial demonstrated that supplemental breast MRI screening in women with extremely dense breasts detected 16.5 cancers per 1,000 women screened versus 5.4 with mammography alone, significantly reducing interval cancers. Breast ultrasound is an alternative supplemental screening tool with lower sensitivity than MRI but greater accessibility and lower cost. Many states now mandate that women be notified of their breast density and informed about supplemental screening options.
The DENSE trial demonstrated supplemental breast MRI detected 16.5 cancers per 1,000 in women with extremely dense breasts
What Should You Expect During a Mammogram?
A screening mammogram takes about 20 minutes. You'll undress from the waist up and stand in front of the mammography machine. Each breast is compressed between two plates while X-ray images are taken from different angles. You'll receive results within 1-2 weeks, or sooner if required by state law.
Preparation tips include scheduling for the week after your period (when breasts are least tender), avoiding deodorant, lotion, or powder on your chest and underarms on the day of the exam, and wearing a two-piece outfit for convenience. If you have breast implants, inform the facility when scheduling as additional views are needed. Bring any prior mammogram images if you're going to a new facility so the radiologist can compare.
Results are communicated using the BI-RADS (Breast Imaging Reporting and Data System) classification. BI-RADS 1 (negative) and 2 (benign finding) are normal results. BI-RADS 0 means additional imaging is needed — this occurs in approximately 10% of screening mammograms and usually leads to a benign finding. BI-RADS 3 is probably benign with short-interval follow-up recommended. BI-RADS 4 and 5 are suspicious findings that require biopsy. Understanding these categories can reduce anxiety while awaiting results.
