How often should you have a mammogram? Breast density and risk can inform decision

Women between the ages of 50 and 74 may benefit from more or less frequent mammography screening than is generally recommended, depending on breast density and risk. For average-risk women with lower breast density, which comprises a large proportion of the population, triennial screening offers about the same or better balance of benefits and harms as biennial screening and is also cost-effective. Higher-risk women with dense breasts may fare better with annual screening. Findings from a collaborative modeling study are published in Annals of Internal Medicine.

Accepted clinical guidelines recommend biennial mammography screening for women aged 50 to 74. These recommendations also advocate shared decision making regarding screening frequency that takes into consideration an individual woman's preferences, risk level, and breast density. However, there is limited data available to guide clinicians and women in making these decisions.

Researchers from the Cancer Intervention and Surveillance Modeling Network, collaborating with the Breast Cancer Surveillance Consortium (BCSC), used three well-established models to evaluate outcomes using various screening intervals for digital mammography among subgroups of women based on age, risk, and breast density. The outcomes were projected for women 50 or older who were deciding whether to initiate (or continue) biennial screening until age 74 or to have annual or triennial screening.

The models showed that average-risk women with lower breast density could safely and effectively extend their screening interval to once every three years, which could reduce false-positives, biopsies, and overdiagnosis with minimal effect on breast cancer deaths averted. Women at higher risk for breast cancer and with dense breasts would reap greater benefit from annual screening. The authors suggest that these findings could be useful for guiding shared decision making and tailoring screening intervals.