Abstract
In order to consider the introduction of mammography for breast cancer screening in women aged under 50, we compared the findings on diagnostic mammograms in women aged 40-49 with those in women aged 50 or over.
Methods : From July to December 1998, 1, 777 patients underwent diagnostic mammography in our outpatient clinic. We investigated these mammography reports regarding the findings, the assessment categories, and the outcomes.
Results : Proportion of the dense breast in women aged 40-49 and those aged 50 or over was 27 % and 12%, the positive predictive value was 28% and 44%, and the false negative rate was 8.5% and 4.7%, respectively. There are 8 patients with breast cancer whose mammogram could not show any abnormalities. The pattern of small nodule (T1 tumor) in extremely dense breast tissue were observed in 5 of these false negative patients.
Conclusion : Although the positive predictive value for women aged 40-49 was lower than the value for women aged 50 or over because of the difference in parenchymal density, the sensitivity for women aged 40-49 held 90% or more. We can expect the effectiveness of mammographic mass-screening for breast cancer in women aged 40-49.
