To reduce their risk of getting breast cancer or dying from it, women should engage in regular physical activity and maintain a normal body weight.

Death rates from breast cancer have dropped by 2.3 percent a year since 1990, the report found, and the decline is most pronounced among younger women.

The incidence of breast cancer actually increased by 0.3 percent a year from 1987 to 2002, the latest year for which figures are available, the report found. But that increase was limited to women age 50 and older -- among women 40 to 49, the number of cases declined during the same period. And for women under 40, there was little change, the report, Breast Cancer Facts & Figures 2005-2006, found.

5-Year Survival Rate Is 88%

The report is issued by the society every two years. Initially published in 1996, the report gives estimates of cases and deaths for the current year. It also offers information on known risk factors for breast cancer, factors that influence survival, and the latest information on prevention and early detection, treatment, and continuing research on the disease, the society said.

Except for skin cancer, breast cancer is the most frequently diagnosed cancer among US women, with 211,240 new cases of invasive breast cancer expected to be found in 2005. Over 40,000 women will die from the disease this year, the society predicts.

While the overall death rate from breast cancer decreased by 2.3 percent annually from 1990 to 2002, death rates declined by 3.3 percent a year among women younger than 50, and by 2.0 percent a year among women 50 and older.

The overall five-year relative survival rate for women diagnosed with breast cancer is now 88 percent, and the 10-year relative survival rate is 80 percent, according to the report.

The report also found that the five-year relative survival rate for white women is 90 percent, compared to 76 percent for African-American women. The difference was attributed, in part, to later detection of the disease in minority women, the society said.

The incidence of male breast cancer has increased by 1.1 percent a year from 1975 to 2002, for reasons that are unknown, the report said. According to the society, close to 1,700 American men develop invasive breast cancer each year.

Incidence Increasing in Women over 50

Explaining the increased incidence rate among older women, Dr. Ahmedin Jemal, program director for cancer occurrence at the American Cancer Society, cited mammography. As more women get the exams, he said, the cancers are being detected earlier.

Historical changes also play a role in the increase, according to the society, particularly reproductive patterns such as delayed childbearing and having fewer children.

Jemal said the obesity epidemic might also explain why the incidence of breast cancer is increasing among women over 50, but not in younger women. "In premenopausal women, obesity protects them against breast cancer [although it is still crucial to avoid obesity to avoid other health risks]. For postmenopausal women, obesity is a risk factor."

The lower risk among obese younger women, he explained, is likely due to their tendency to have menstrual cycles in which they do not ovulate, thereby lowering levels of circulating hormones, including estrogen, which has been linked to breast cancer.

Overall, the report paints a fairly encouraging picture, Jemal said. "I think it is good news, in that most of the breast cancer cases diagnosed are at an early stage."

"Over 63 percent of women diagnosed with breast cancer are diagnosed at a localized stage, where survival is almost 98 percent," he said.

Better Drugs

Dr. Robert J. Morgan Jr., a staff physician at the City of Hope Comprehensive Cancer Center in Duarte, Calif., predicts the decrease in death rates will become even more pronounced. "I think we will see an even greater decrease next time the report is issued," he said.

He cites three reasons for the decline in deaths from breast cancer. "Our ability for early detection is certainly increasing," he said. "Our drugs are getting better. And we are beginning to show there are things that can be done to patients who have had breast cancer to reduce the chance of it recurring."

"Studies are supporting the idea of lifestyle changes" to prevent recurrence, he said. While physicians have always thought that improving diet and getting more exercise would decrease recurrence risk, Morgan said studies are now being published that buttress the value of these lifestyle changes.

What can women do to reduce their risk of getting breast cancer or dying from it? They should engage in regular physical activity and maintain a normal body weight, Jemal said, as well as continue to get regular mammograms.

More information: To learn more about breast cancer and its prevention, visit the American Cancer Society.