Systematic estimation of breast cancer risk appears justified in postmenopausal women

Screening for breast cancer risk in all postmenopausal women, using a combination of risk factors and breast density, can identify women at high risk of disease, according to systematic literature reviews and meta-analyses reported in the March 10 online issue of the Journal of the National Cancer Institute. The reviews and meta-analyses also support the use of chemoprevention in women at high risk of disease and the value of positive lifestyle changes in all women irrespective of their breast cancer risk.

Although models have been developed to estimate a postmenopausal woman's risk of breast cancer, it has not been clear whether the routine use of the models in clinical practice is supported by clinical trial data.

To determine whether regular screening for the risk of breast cancer was justified, Steven Cummings, M.D., of the San Francisco Coordinating Center at the California Pacific Medical Center Research Institute in San Francisco, and colleagues used systematic literature reviews and conducted meta-analyses of clinical trials that examined the predictive accuracy of risk assessment models and breast density measurement to identify women at high risk of disease. They also reviewed prospective studies that examined the impact of lifestyle factors on breast cancer risk, and they conducted a meta-analysis of clinical trials with tamoxifen and raloxifene for primary prevention of breast cancer.

The researchers found that risk assessment models that were based on demographic characteristics and medical history alone had moderate ability to discriminate women's risk of breast cancer. However, accuracy improved when the models were combined with breast density information. A meta-analysis supported the efficacy of either tamoxifen or raloxifene for primary prevention of breast cancer. Finally, a systematic review and meta-analysis also found that exercise, weight reduction, low-fat diet, and reduced alcohol intake may reduce a woman's risk of breast cancer.

"In conclusion, evidence from these reviews supports systematic assessment of postmenopausal women for breast cancer risk with risk factors and assessment of breast density. Chemoprevention should be considered for those at high risk; however, cost-benefit analyses are needed to provide specific recommendations about who should be offered chemoprevention," the authors write. "Several lifestyle changes can be recommended to postmenopausal women, regardless of their estimated risk category."

Source: Journal of the National Cancer Institute