Screening, Therapies Behind Drop in Breast Cancer Death Rates

WEDNESDAY, Oct. 26 (HealthDay News) -- About 1,000 fewer American women die from breast cancer each year, but experts are still debating whether screening or better treatments are responsible for the drop.

Now, a new study gives credit to both.

Screening is responsible for about 46 percent of the decline in the death rate from breast cancer, while adjuvant treatments such as chemotherapy and tamoxifen are responsible for an estimated 54 percent of the reduction in deaths, according to the study.

"The average woman can gain some comfort knowing that both these things that are going on are important," said study co-author Donald Berry, chairman of the department of biostatistics and applied mathematics at the University of Texas M.D. Anderson Cancer Center in Houston.

"We found that the effects are additive. Screening helps independent of chemotherapy and therapy helps independent of screening. Of course, surgery is still critical," he said.

Results of the study appear in the Oct. 27 issue of the New England Journal of Medicine.

According to a report issued by the American Cancer Society (ACS) in September, the death rate for breast cancer is dropping by about 2.3 percent a year. According to Berry''s study, the death rate from breast cancer has declined by 24 percent since 1990. While that news is encouraging, as many as 40,000 women will still die this year from breast cancer, according to ACS estimates.

To assess the reason for the declining death rates, the National Cancer Institute challenged seven different cancer centers to come up with a statistical model that measured the effect of screening and of adjuvant treatments on the rate of death from breast cancer.

Each center came up with slightly different answers, but Berry said that overall, the researchers concluded that adjuvant therapy was responsible for a slightly higher percentage of the decline than screening: 54 percent versus 46 percent.

Because these findings are based on statistical modeling, Berry said, "We don''t know the answers for sure. There''s still some uncertainty because we don''t have perfect data."

However, he added, "There''s no uncertainty that treatment -- as used in this country -- is very effective at prolonging survival."

"Although less certain, screening indeed appears to be effective at lowering mortality," Berry said.

Debbie Saslow, director for breast and gynecologic cancer at the American Cancer Society, said, "Both early detection and treatment are important for keeping the death rate down."

The bottom line from this study, Saslow said, is that women should "get screened and if diagnosed with breast cancer, get appropriate treatment."

She said "a lot of women are afraid to go to the doctor and get mammograms because they''re afraid to find out they have breast cancer. But, the real fear should be to find out that you''ve had breast cancer for a long time and have missed treatment opportunities."

The ACS currently recommends that every woman begin getting an annual mammogram at age 40. If you have a strong family history of the disease, talk with your doctor. You may need to start screening earlier, at about 30, Saslow said, and you may also need to have an ultrasound or MRI in addition to an annual mammogram.

More information

The American Cancer Society has more information on breast cancer.

SOURCES: Donald Berry, Ph.D., professor and chairman, department of biostatistics and applied mathematics, University of Texas M.D. Anderson Cancer Center, Houston; Debbie Saslow, Ph.D., director, breast and gynecologic cancer, American Cancer Society, Atlanta; Oct. 27, 2005, New England Journal of Medicine

Last Updated: Oct. 27, 2005