False-positive mammogram results deter women from attending further screening appointments and undermine the effectiveness of breast cancer screening programs, according to a study published in the 18 June issue of the Medical Journal of Australia.

Dr Elizabeth Wylie from BreastScreen WA, and coauthors found that 70.7% of Western Australian women with a true-negative screening result returned to screening within 27 months compared with 67.6% of women who received a false-positive result (when a mammogram is positive but there is no breast cancer found with further tests).

Additionally, women who had a false-positive mammogram followed by an invasive procedure were less likely to participate in rescreening than those who had further imaging alone. "Our results show that women with a false-positive [mammogram] are deterred, to a small extent, from participation in future screenings", the authors wrote.

According to the authors, around 44 out of 1000 women receive false-positive screening results at BreastScreen WA, the state branch of BreastScreen Australia.

They wrote that although this number was small, the combined effect over time might be considerable given that 32.4% of women who start screening at age 50 and who participate in 10 consecutive screening rounds were likely to have at least one false-positive recall.

BreastScreen WA screens about 55% of Western Australian women aged 50-69 years every 2 years - but it had noted falling participation rates over recent years that could not be explained by attrition to private mammography.

The authors concluded that mammographic screening services should try to keep their falsepositive result rates low to prevent women being deterred from screening.