Two new studies that suggest mammograms won't save many lives of women under 50 haven't changed the positions of the American Cancer Society and American Medical Association.
The researchers said regular mammograms significantly reduce the risk of dying of breast cancer for women over 50, but offer little lifesaving benefit for women in their 40s. They arrived at their conclusion after reviewing 13 studies.The cancer society and the AMA, however, continue to recommend that women get a mammogram every year or two starting at age 40.
An AMA spokesman said the 13 studies varied in design and conduct, and that most were done outside the United States and failed to consider any factors other than death rates.
The American Cancer Society said it reviewed the same 13 studies and found no reason to change its belief that women ages 40 to 49 should be screened every year or two.
In 1993, the National Cancer Institute stopped recommending that women in their 40s get regular mammograms, saying there's no evidence the examinations significantly reduce breast cancer deaths in that age group.
Authors of the review of 13 studies couldn't find any significant evidence, either.
"This study's important message for women is that those 50 to 74 who underwent screening mammography had a 26 percent reduction in breast cancer deaths compared with women who did not," said the lead author, Dr. Karla Kerlikowske, an assistant clinical professor of medicine and epidemiology and biostatistics at the University of California at San Francisco.
Routine mammograms yielded an insignificant reduction in breast cancer deaths in women ages 40 to 49 after the same length of follow-up - seven to nine years, her team found. The reduction was 7 percent, but researchers couldn't be sure the number wasn't due to chance.
The findings were published in today's issue of The Journal of the American Medical Association. The journal includes a separate cost-benefit analysis of mammography screening, which concludes that standard health insurance should not pay for the procedure for women younger than 50 or older than 69.
The Rand Corp. estimated that a health plan covering 500,000 people would spend $11.9 million over six years to give biennial mammographies to all 50- to 69-year-old women - and would save 11.9 lives per year.
Screening women ages 40 to 49 every two years would cost an additional $11.7 million over seven years and would save zero to 1.1 lives per year, said researchers led by Dr. Herman Kattlove.
Screening women ages 70 to 74 would cost $1.6 million over three years and would not save a significant number of lives, the researchers said.
Rand, based in Santa Monica, Calif., is an independent think tank.
Dr. Melody Cobleigh, director of the Comprehensive Breast Center at Rush-Presbyterian-St. Luke's Medical Center in Chicago, said she will continue to urge women under 50 to get mammograms because they save lives.
"Over the weekend, I went through the records of patients I'd seen newly diagnosed with breast cancer in 1994," she said Tuesday.
"In our 120 cases, there were 50 women between ages 40 and 50. Thirty-five percent were diagnosed on the basis of screening mammography."