When is the optimal time to start screening for breast Ca?

May 10, 2012

Digital mammograms every other year in women aged 40 to 49 who have double the average risk for breast cancer have about the same risk?benefit ratio as biennial screening of average-risk women starting at age 50.

Compared with film mammography, digital mammography yields more false-positive results.

Individualized, risk-based screening for breast cancer is advisable.

Biennial screening with digital mammography for women 40 to 49 years of age who have double the average risk for breast cancer has about the same risk–benefit ratio as biennial screening of average-risk women starting at age 50, according to the results of a recent comparative modeling study published in Annals of Internal Medicine (2012;156[9]:609-617).

Researchers from the Netherlands and the United States used 4 microsimulation models to assess the benefits (ie, number of breast cancer deaths averted and number of life-years gained) and harms (ie, number of false-positive results) associated with film and digital mammography performed annually and biennially and starting at different ages, depending on a woman’s risk for disease.    

They found that biennial screening of women aged 50 to 74 who are at average risk for breast cancer results in the same ratio of false-positive results to life-years gained as biennial screening with digital mammography of women at twice the average risk, starting at age 40 years (median threshold relative risk [RR], 1.9 [range across models, 1.5 to 4.4]). Annual screening with digital mammography increased the threshold RRs (median, 4.3 [range, 3.3 to 10]), as did using false-positive findings/deaths averted as the outcome measure instead of false-positive findings/life years gained.

In addition, digital mammography resulted in substantially more false-positive results than did film mammography. As a result, the harm–benefit ratio for film mammography was more favorable than for digital.

The authors conclude that their results point toward the need for individualized, risk-based screening.

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