Lowering the threshold for recalling patients for additional assessment after a mammogram can detect more breast cancers earlier, but the benefit levels off, according to a new study published in the Journal of the National Cancer Institute.

Breast cancer screening programs aim to improve patient mortality and decrease morbidity by detecting high numbers of early-stage cancers without increasing the number of false positives - women recalled for additional assessment who do not have cancer. There is a relationship between the recall rate and the false-positive rate, but it has remained unclear.

To estimate the effect of changes in the recall rate on the earlier detection of breast cancers, Johannes D. M. Otten, M.Sc., of Radboud University Nijmegen Medical Centre in Nijmegen, the Netherlands, and colleagues conducted a blinded review of interval and screen-detected cancers in the Dutch screening program. Because the recall rate in the Netherlands is the lowest worldwide - less than 1% - the researchers were able to estimate how changing this rate might change both detection and false-positive rates.

They found that increasing the recall rate in the Dutch program to 2% would increase the detection rate from 4.20 cancers per 1,000 women to 4.52 cancers per 1,000 women due to the earlier detection of interval cancers. Increasing the recall rate to 3% or 4% would increase the detection rate to 4.58 cancers per 1,000 women and 4.63 cancers per 1,000 women, respectively. For each 1% increase in the recall rate above 5%, the detection rate would increase by 0.03 cancers per 1,000 women, but less than 10% of the women recalled for further assessment would actually have cancer.

SOURCE:
Journal of the National Cancer Institute, May 18, 2005