Poor detection lowers mammography sensitivity in young women
MedWire News: The reduced effectiveness of mammographic screening in women in their forties is primarily due to a lower rate of detection compared with older women, rather than a faster tumor growth rate, US researchers report.
Sylvia Plevritis (Stanford University, California) and colleagues explain that the poorer sensitivity of mammographic screening in younger women is traditionally attributed to faster tumor growth rates and a reduced ability to detect tumors because of a higher breast density than in older women.
To estimate the relative contribution of biologic (tumor growth) versus technological (mammographic tumor detectability) factors in screening outcomes of younger (40-49 years) compared with older (50-69 years) women, Plevritis and team used a computer-based Breast Cancer Screening Simulator.
The researchers created hypothetical screening scenarios whereby they could estimate the median tumor size detectable on a mammogram, and the mean tumor growth rate among women in both age groups.
They found that 79% of poorer mammography screening sensitivity in the younger women was because of reduced mammographic tumor detectability, while only 21% was because of faster tumor growth.
The results were similar for other screening outcomes such as tumor size at detection, lifetime gained, and breast cancer mortality.
"The age-specific differences in mammographic tumor detection contribute more than age-specific differences in tumor growth rates to the lowered performance of mammography screening in younger women," say Plevritis and co-authors in the Journal of the National Cancer Institute.
One limitation of the analysis, they note, is that it did not take into account that low mammographic tumor detectability could be considered a risk factor for breast cancer.
"More research is needed to not only establish a better relationship between mammographic breast density and breast cancer risk, but also to understand the differences in tumor characteristics in dense versus non-dense breast tissue," Plevritis and team conclude.
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By Laura Dean