More Evidence for Mammograms at 40
Mammograms for Women Starting at 40 Find Smaller, More Treatable Breast Cancer
July 28, 2003 -- First women were told they needed annual mammograms when they reached age 40. Then came reports that those under 50 reaped little benefit from the practice. The debate continues, but a new study may help bolster the case in favor of early and frequent breast cancer screening.
Researchers from Philadelphia's Fox Chase Cancer Center report that surveyed breast cancer patients who were 40 or older and had had annual or frequent mammograms had smaller and less invasive tumors at diagnosis than women who never got mammograms or got them infrequently. Women who had annual mammograms were also more likely to be candidates for breast-sparing surgery.
"It stands to reason that smaller tumors at diagnosis would mean more women were able to have lumpectomies instead of mastectomies, but I believe this is the first study to confirm this," researcher Gary M. Freedman, MD, tells WebMD.
Fodder for Debate?
Because the study did not follow the patients after treatment, Freedman acknowledges it will probably do little to mollify critics who say annual mammograms offer no obvious survival advantage to women aged 40-50.
In a widely reported literature review, published in 2000, researchers in Copenhagen concluded no such survival advantage could be shown in women of this age group. A 2002 study involving 90,000 women in Canada found no evidence that routine mammograms benefited women in their 40s.
"If there were no controversy, there would be no need for a study like ours," the Fox Chase radiation oncologist says. "The hope is that this research will add to the debate in a meaningful way."
In the study, conducted between July of 1995 and October of 2001, Freedman and colleagues questioned 1,591 women aged 40 or older with newly diagnosed breast cancer about their mammography history. The findings are reported in the September 1 issue of the journal Cancer.
Average screening interval was estimated by calculating each patient's age and the number of mammograms they reported prior to diagnosis. The researchers found 26% of patients who reported annual screening had the early, noninvasive form of breast cancer known as ductal carcinoma in situ (DCIS), compared with 21% of patients screened less often and 15% of patients who had never been screened.
Similarly, 56% of women who had yearly screenings had early-stage tumors, compared with 50% of patients screened less often and 32% of patients with no history of having had a mammogram. And 61% of women who reported any history of mammography were considered candidates for breast-conservation surgery, compared with 41% of women who had never been screened.
'More Evidence' for Annual Screening
Freedman says the findings favor annual mammograms for all women starting at age 40. That is the recommendation of the American Cancer Society (ACS), while the National Cancer Institute and the U.S. Preventive Services Task Force say women should be screened every one to two years.
"If nobody was dying from breast cancer then I think we could have a serious debate about whether too many women were being screened and treated for this disease," Freeman says. "But we still have 40,000 women dying of breast cancer each year, and yearly mammography can help change that."
ACS deputy chief medical officer Len Lichtenfeld, MD, agrees, calling the Fox Chase findings "one more piece of evidence" in favor of annual screening.
"The message has been to get a mammogram," he tells WebMD. "This study says that women who have annual mammograms can increase their chances of being diagnosed at a very early and treatable stage."