Mammography Effective in Reducing Breast Cancer in Elderly

January 28, 2000
News Office: Eve Harris (415) 885-7277

Screening mammography can reduce the risk of advanced breast cancer in elderly women, according to a University of California, San Francisco study.

The study found that women who undergo screening mammography in their 70s had a 43 percent less chance of developing metastatic or advanced breast cancer than women who were not screened. The reason is that screening catches the cancer in the early stages, said Dr. Rebecca Smith-Bindman, lead author of the study and a radiologist at UCSF Medical Center. Metastatic or advanced cancer means that the tumors have spread to other parts of the body.

The study found that women who undergo screening mammography in their 70s had a 43 percent less chance of developing metastatic or advanced breast cancer than women who were not screened. The reason is that screening catches the cancer in the early stages, said Dr. Rebecca Smith-Bindman, lead author of the study and a radiologist at UCSF Medical Center. Metastatic or advanced cancer means that the tumors have spread to other parts of the body.

The UCSF study looked at 690,993 women, aged 66 to 79 years old, who were California Medicare beneficiaries from January 1992 to December 1993. It found that among the 300,000 plus women who were screened, their rates of advanced breast cancer were 43 percent lower than the rates of women who were not screened.

"Metastatic breast cancer reflects a missed opportunity to treat the disease early before it spreads," Smith-Bindman said. "Screening finds the disease early when it is potentially curable. That's the whole point of screening."

Breast cancer mortality rates have declined in the past decade for women ages 50 to 69, in part because of an increase in the use of mammography, she said. However, women ages 70 to 79 have not seen the same kind of improvement in breast cancer mortality rates. For example, in California, women age 70 to 79 experienced a 10 percent decrease in breast cancer mortality from 1989 to 1993, Smith-Bindman said. Women ages 50 to 69 experienced a 19 percent drop in breast cancer mortality during those same years.

"Women in their 70s undergo screening mammography less often than younger women, and it may be why these women have not had the same decline in breast cancer mortality, since they do not undergo screening as often," Smith-Bindman said.

While breast cancer screening can reduce the rates of metastatic breast cancer in elderly women, it can also uncover early stage, non-invasive tumors in women who would have remained symptom free even in the absence of screening, she said. But since it's impossible to tell which of these early stage tumors will be dangerous, most are surgically removed.

Elderly women should weigh their treatment options, Smith Bindman said. For example, a patient with early stage cancer most likely wouldn't need a mastectomy, but could need a lumpectomy. A lumpectomy is the surgical removal of a lesion. A mastectomy involves removing the breast.

In addition to Smith-Bindman, co-authors include Dr. Karla Kerlikowske, UCSF assistant professor of medicine and epidemiology and biostatistics; Tebeb Gebretsadik, MPH; California Medical Review Inc.; and Dr. Jeffrey Newman, MPH, UCSF assistant clinical professor of medicine. This study was funded by a National Cancer Institute Breast Cancer SPORE grant, the Health Care Finance Administration and a Breast Cancer Surveillance Consortium Cooperative agreement.