Risk assessment tool for breast cancer may not be reliable for everyone
November 8, 2008 by Marijke Durning, RN
Filed under Diseases & Conditions
The Mayo Clinic has a breast cancer risk assessment tool that is designed to predict which women have the greatest risk of developing breast cancer. However, researchers found that the tool wasn’t reliable in predicting breast cancer in women who had atypical hyperplasia, a precancerous condition.
The model, or tool, is called the Gail Model and to calculate breast cancer risk, the model takes into account if the woman has a family history of breast cancer, how old she is, how old she was when she began menstruation and when or if she had her first baby, and how many breast biopsies she may have already undergone.
According to a press release issued by the Mayo Clinic after it had run a study checking for the tool’s accuracy in women with atypical hyperlasia:
Mayo Clinic researchers tested the Gail model in 331 women with atypia who had benign breast biopsies at Mayo Clinic between 1967 and 1991. Of these women, 58 developed cancer during an average of 13.7 years of follow-up. In contrast, the model predicted that 34.9 women would develop breast cancer in that period.
Using these and other data, researchers also calculated the model’s performance for individuals using the concordance statistic (c-statistic), which reflects how closely the actual timing of breast cancer events aligned with model predictions. A c-statistic of 0.5 is observed if the predictions are no better than random chance; a c-statistic of 1.0 is observed if the predictions are perfectly concordant with the actual outcomes. In this study, the c-statistic was 0.5, reflecting that the Gail model worked no better than a coin flip in predicting which of the women with atypia would develop invasive breast cancer.
When assessed across other groups of women without respect to the presence of atypia, the Gail model typically performs better. In that setting, it has been shown to predict approximately the same number of breast cancers that later occur.
This is an interesting finding and well worth noting as physicians try to find better ways to predict cancer.
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Tags: cancer blog, breast cancer, breast cancer risk, Gail model, breast cancer assessment tool
