MONDAY, April 17, 2006 (HealthDay News) -- Less frequent mammograms may explain why black women tend to be diagnosed with more breast cancers at a later stage, and why more die from the disease compared with white women, researchers report.
"African-American women, particularly, are diagnosed with larger, more aggressive tumors than white women," said study lead author Dr. Rebecca Smith-Bindman, an associate professor of radiology at the University of California, San Francisco. "As a result, their survival is worse."
According to her team's report, during the 1990s, death rates from breast cancer in the United States decreased with the increase in mammography. This decrease in death rates mostly benefited non-Hispanic white women, however. During the same period, the mortality rate for black women did not change significantly.
The likely reason: White women were more likely than black women to be screened every one to two years, the researchers found.
While 72 percent of white women underwent regular screening, just 63 to 68 percent of black, Hispanic, Asian and Native-American women were screened regularly.
Moreover, black, Hispanic and Asian women were more likely than white women to have never had a mammogram. That means many of these women had their first mammogram only after symptoms or a physical examination led to a breast-cancer diagnosis.
The report appears in the April 18 issue of the Annals of Internal Medicine.
In the study, the UCSF team collected data on more than one million women 40 years of age and older who had at least one mammogram between 1996 and 2002. Among these women, 17,558 cases of breast cancer were diagnosed.
The researchers found that 18 percent of white women with breast cancer were inadequately screened before being diagnosed with breast cancer, compared with 34 percent of black, 24 percent of Hispanic and 27 percent of Native-American women.
Although black and Hispanic women had more severe breast cancer, once the women were grouped by their use of mammography, differences in survival disappeared, Smith-Bindman said. "Adequate use of mammography is an ongoing problem," she said. "When women had adequate mammography, all the difference in breast cancer went away."
There is probably a combination of factors that account for the disparity in screening, Smith-Bindman said. "There may be financial and cultural barriers," she said.
One expert thinks there may be a genetic difference between black women and white women that could account for part of the difference in the severity of breast cancer seen in black women.
"When women are equally screened, you no longer see a difference in the size of the tumor or the stage of the tumor between white and African-American women," said Dr. Mary H. Barton, an epidemiologist with the U.S. Agency for Healthcare Research and Quality, and author of an accompanying editorial.
"However, there was one marker of tumor identity that was different between African-American and white women," Barton said. "This means that it may not just be bad medical care and less frequent use of mammography that is the cause that black women die more often from breast cancer than white women. Maybe there is a genetic link."
Barton also thinks efforts are needed to increase screening among black and Hispanic women. Women and their doctors need to be reminded that getting a regular mammogram is vital.
"Let's not just focus on the doctor, let's go to the patients and show how important this is," Barton said. "That will make both of them more likely to ask for it and more likely to follow through,"
More information
For more on breast cancer, head to the U.S. National Cancer Institute.
