What is the recommended interval for the next mammogram for an asymptomatic average-risk woman with a negative mammogram and no family history of breast cancer?

Mammography Screening Interval for Average-Risk Women with Negative Mammogram

For an asymptomatic average-risk woman with a negative mammogram and no family history, the next mammogram should be performed in 1-2 years, with the specific interval depending on age and shared decision-making. 1

Age-Specific Recommendations

Women Under Age 50

• Annual mammography (1 year interval) is recommended by the American College of Radiology for women aged 40-49 years 1
• The American College of Obstetricians and Gynecologists recommends screening every 1-2 years for women aged 40-50, with the decision made through shared decision-making 1
• The American Cancer Society recommends annual screening for women aged 45-54 years 1

Women Age 50 and Older

• Annual or biennial screening (1-2 year intervals) is appropriate, with biennial screening being particularly reasonable after age 55 1
• The U.S. Preventive Services Task Force recommends mammography every 1-2 years for women aged 50-69 1
• The Canadian Task Force on Preventive Health Care recommends screening every 2 years for women aged 50-69 1

Evidence Supporting Different Intervals

Annual screening provides superior mortality reduction compared to less frequent screening. 1

• Annual screening reduces breast cancer mortality by 40%, compared to only 32% reduction with biennial screening 1
• Interval breast cancers (cancers diagnosed between screening mammograms) occur with higher frequency in women undergoing biennial or triennial screening compared to annual screening 1
• Among women with negative mammograms, 30.2% of subsequent cancers are diagnosed as interval cancers (before the next scheduled screening), while 69.8% are detected at the next screening mammogram 2

Practical Algorithm for This Patient

Given the question presents an average-risk woman with:

• Negative mammogram
• No symptoms
• No family history

The answer is (C) 2 years if she is age 50 or older and opts for biennial screening through shared decision-making, or (B) 1 year if she is under 50 or prefers annual screening for maximum mortality reduction. 1

Most Conservative Recommendation

Annual screening (1 year) provides the greatest mortality benefit and should be offered to all average-risk women starting at age 40. 1

Important Caveats

• Age 40-49: The evidence shows more variability in recommendations, with some guidelines supporting annual screening and others suggesting 1-2 year intervals based on shared decision-making 1
• Age 50-69: This is considered the optimal age group for screening with the strongest evidence for mortality reduction 1, 3
• After age 75: Screening should continue as long as the woman has good overall health and life expectancy of at least 10 years, rather than stopping at an arbitrary age 1, 4

Common Pitfalls to Avoid

• Do not extend screening intervals beyond 2 years for average-risk women, as this significantly increases the risk of interval cancers and reduces mortality benefit 1, 2
• Do not assume a negative mammogram eliminates the need for continued screening—breast cancer can develop between screening intervals, particularly in younger women and those with dense breasts 1, 2
• Do not use 6-month intervals for routine screening in average-risk women—this interval is reserved for BI-RADS category 3 (probably benign) findings requiring short-term follow-up 1, 5