WEDNESDAY, Dec. 15, 2004 (HealthDayNews) -- Women age 50 and above who get screening mammograms every two years instead of annually may not face an increased risk of being diagnosed with late-stage breast cancer, a new study suggests.
"For women ages 40 to 49, we did see a benefit of a one-year interval over a two-year" hiatus between screenings, said Emily White, a researcher at the Fred Hutchinson Cancer Research Center in Seattle and lead author of the study, which appears in the Dec. 15 issue of the Journal of the National Cancer Institute.
White and her colleagues analyzed data collected by seven mammography registries in the United States. They looked at whether the 2,440 women who had been diagnosed with breast cancer after getting screened every two years were more likely to have been diagnosed with late-stage cancer compared with 5,400 women who were diagnosed with breast cancer after getting screened every year.
Among those 50 and over, there was no increase in the risk of a late-stage breast cancer diagnosis for those who got screened every two years compared with those screened annually. "We did see a difference under age 50," White said.
In women 40 to 49 years old, 28 percent of those diagnosed with late-stage breast cancer got screenings every two years. Among those who got annual screenings, the rate was 21 percent.
Overall, in other age categories, the percent of late-stage cancers diagnosed was within 1 percent of each other regardless of whether women were screened every year or every two years, White said. For instance, among women aged 50 to 59, 21 percent of those screened annually had late-stage breast cancer, while 22 percent of those screened every two years did.
The findings make sense, White said, because tumors generally grow faster in women under age 50.
Currently, the American Cancer Society recommends annual mammography for women aged 40 and above; the U.S. Preventive Services Task Force recommends screening every one to two years for women aged 40 and older.
The study echoes findings of other research, but doesn't mean women should change their mammogram screening habits, said Robert Smith, director of cancer screening for the American Cancer Society.
"It validates what the American Cancer Society has been saying for some time and what previous studies have shown: that breast cancer grows faster in premenopausal women," Smith said.
The findings don't mean that older women should lengthen the time between mammograms, he said. But the society will focus on the study findings, Smith said. "We will consider these data very carefully when we next update our guidelines," he said.
White agreed. "I don't think women should change their behavior based on a single study," White said. The findings have more potential use for policy-makers than for personal decision-making about screening at this time, White said.
"This is more information that will be useful when the next set of recommendations come out," she said. Her advice for women is to "wait and see how this study is interpreted by the national organizations that make these recommendations."
To learn more about detecting the disease early, visit the American Cancer Society.