NEW YORK, Oct 21 (Reuters Health) -- Many women may place too much faith in the ability of mammography to catch breast cancer at its earliest stages, results of an Australian study suggest.
In a survey of 115 women that asked them to estimate the accuracy of mammograms, one-third believed screening detected at least 95% of breast cancer cases -- an "unrealistically high expectation," according to researchers led by Dr. Alexandra Barratt of the University of Sydney, Australia.
Reporting in the current issue of the Journal of Epidemiology and Community Health, the researchers added that 40% of women thought the breast x-rays "should realistically" detect all cancers.
In actuality, Barratt's team notes, mammography detects between 75% and 94% of breast cancer cases, depending on age -- the failure rate is higher for women younger than age 50 because of their more dense breast tissue. Just 35% of survey respondents made estimates within the correct range.
The women's tendency to overestimate the reliability of mammography was coupled with the common belief that women should be financially compensated when the test initially fails to detect cancer, but further screening catches it at a later stage. Forty-five percent favored financial compensation if the failure was due solely to mammography's inherent failure rate; nearly all -- 93% -- favored compensation if someone involved in the screening made an error.
While the investigators note that they are unaware of anyone in Australia who has successfully sued for an inaccurate cancer screening, there remains the concern that if such claims are successful in the future, the financial burden "could render breast and cervical screening programs in Australia unsustainable." Similar concerns, they add, have been expressed in the United States.
In the US, the National Cancer Institute (NCI) recommends that women at average risk for breast cancer have a mammogram every 2 years beginning at age 40, and every one to two years after age 50. Women at high risk, such as those with a personal or family history of breast cancer, should discuss their screening needs with their physician. According to the NCI, a new technique called digital mammography is likely to improve the test's accuracy in coming years. Currently under study, this technology produces clearer images of breast tissue and allows computer-assisted diagnosis of cancer.
