Using a combination of risk factors, including breast density, provides the most accurate method to date for postmenopausal women to determine if they are at risk for developing breast cancer. That's the finding of a new meta-analyses and literature review in the March 10th online issue of the Journal of the National Cancer Institute.

The study also supports the valuable role that some lifestyle changes can make in helping all women reduce their risk of breast cancer, and the effectiveness of using chemoprevention in women at high risk of developing the disease. However, the research found no protective benefit from increasing consumption of fruits and vegetables.

"Most women rely on mammograms to tell them if they currently have breast cancer but know little about their future risk for the disease," says Steven Cummings, M.D., of the San Francisco Coordinating Center at the California Pacific Medical Center Research Institute, and the lead author of the study. "We wanted to identify factors that could be used to help predict a woman's future risk for developing breast cancer, and give them some clear guidelines on what they could do about it."

Cummings and his colleagues carried out a systematic review of the literature on all facets of preventing breast cancer. They also conducted a meta-analysis of clinical trials that tried to measure how accurate various risk assessment models, including measurements of breast density, are at predicting a woman's risk of developing the disease.

The researchers found that breast density, which can be measured in mammograms, is a very strong predictor of future breast cancer risk. Additionally, they found that risk assessment models that used a woman's medical history and demographic characteristics - such as race, age, income, socio-economic status etc ? were only moderately accurate in predicting their risk for breast cancer. However, when combined with measurements of breast density at least one third of the women in the studies could be classified more accurately.

Most women are unaware of their individual risk. "For women at high risk of developing breast cancer these findings are very significant," says Cummings. "If you learn that you are at high risk there are several things you should consider, such as more frequent mammograms or MRIs. We also found that there are a number of treatments such as raloxifene and tamoxifen which, when used for five years, can give you 15 years of protection."

The researchers also found that lifestyle factors such as regular exercise, losing weight, eating a diet lower in fat, and cutting back on alcohol can reduce breast cancer risk for women of all ages, not just postmenopausal women. "What was interesting was that we found that eating more fruits and vegetables didn't seem to make any difference in terms of a woman's risk of breast cancer," says Cummings. "Adding those to your diet may help protect you against other diseases but they don't seem to have any protective benefit for breast cancer."

Cummings says they are now looking at whether a woman who may be at very low risk of developing breast cancer can reduce the frequency of mammograms, getting them every couple of years instead of every year.

Cummings says he hopes the findings will prompt women to be more proactive about their future risk of developing the disease.

"Getting a mammogram is important, but women also need to start asking their physician to help assess what their future risk of breast cancer is, and our study shows that a combination of standard risk factors and breast density measurements is the most accurate method we have right now."