GWEN IFILL: A recent study on mammograms is reigniting a longstanding debate over the benefit of annual screenings.
NewsHour health correspondent Betty Ann Bowser has our report.
BETTY ANN BOWSER: Last year, after a routine mammogram detected two tiny breast cancers, 56-year-old Diana Wright underwent a lumpectomy, four months of chemotherapy and six weeks of radiation.
DIANA WRIGHT, Diagnosed With Cancer: So, I think I was devastated. I was surprised. I was shocked. I was overwhelmed by it all.
BETTY ANN BOWSER: Wright has been following the advice of the American Cancer Society, getting an annual mammogram every year since the age of 40.
DIANE WRIGHT: I feel very fortunate that it was caught then because I had really no symptoms, no signs that I had breast cancer. I felt good. So, without the mammogram, I don't know how long it would be before it was discovered.
BETTY ANN BOWSER: Like millions of American women, Wright thinks mammograms are a good screening tool. But she now finds herself at the center of yet another controversy in the medical community over just how effective annual mammograms really are.
This latest dust-up came on the heels of a new study in The New England Journal of Medicine last month. The study found that annual mammograms do a good job of detecting new small cancers, finding over half of them in the past 30 years. But the researchers said mammograms have not been able to tell the difference between those benign, slow-growing cancers and those that go on to become fatal.
And medical professionals were alarmed at the study's conclusion, that mammograms at best have only had a small effect on the rate of death from breast cancer.
Fran Visco is a best cancer survivor and President of the National Breast Cancer Coalition. She says, from her perspective, the problem with mammography is it leads doctors to overtreat women.
FRAN VISCO, President, National Breast Cancer Coalition: We find situations that are not yet breast cancer, and we treat all of these women with toxic therapy. Most of them do not need it.
BETTY ANN BOWSER: Overall death rates from breast cancer have been declining for the last quarter-century.
But researchers say that's not because of mammography. It's because treatments have improved.
WOMAN: A dramatic turnaround this morning in the argument over mammograms, who should get them and when.
BETTY ANN BOWSER: Just three years ago, mammograms came under attack when a government health task force said women didn't need mammogram screening until the age of 50, and then only every two years.
WOMAN: It's going to lift your breast.
BETTY ANN BOWSER: And since that recommendation, the number of women in their 40s who are getting mammograms has declined slightly, according to a new Mayo Clinic study.
Dr. Rebecca Zuurbier, the chief radiologist at Sibley Memorial Hospital in Washington, D.C., thinks that's a dangerous trend.
DR. REBECCA ZUURBIER, Chief Radiologist, Sibley Memorial Hospital: Confusing women, it's going to cost a lot of lives. And it's also going to result in an excessive treatment required for people that delayed getting their cancer detected. They're not going to be able to save their breast. They're going to have mastectomies or more radical surgeries or more aggressive chemotherapies.
BETTY ANN BOWSER: Dr. Zuurbier strongly disagrees with the findings of the new mammogram study. She says there's plenty of evidence to support annual screening starting at the age of 40.
DR. REBECCA ZUURBIER: One out of six cancers occur in women in their 40s. This is an age group that we don't want to forget. And it is worth it. It has been shown to be effective.
All the screening trials that have done -- been done in the past followed through many decades have shown, looking at the women who presented for screening, a decreased number of deaths from breast cancer, on the order of 40 to 50 percent. That's substantial.
BETTY ANN BOWSER: So far, the American Cancer Society has not changed its recommendation that all women over 40 get regular screening. That's been their policy since 1983.
Dr. Otis Brawley, the society's chief medical officer, sees nothing in the new study that would change that. His greater concern is the large number of women who never get screened.
DR. OTIS BRAWLEY, Chief Medical Officer, American Cancer Society: I am much more concerned about the fact that 35 percent to 40 percent of American women get no mammography screening and no breast cancer screening. I'm even more concerned about the fact that we have numerous studies to show that a substantial portion of the population that are diagnosed with an abnormal mammogram get no follow up to figure out why it's abnormal.
BETTY ANN BOWSER: Dr. Sandra Swain is the president of the American Society of Clinical Oncology. Like Dr. Brawley, she believes all women over 40 should get annual screenings. And she worries that all these conflicting studies with their conflicting set of recommendations leave women confused and ill-informed.
DR. SANDRA SWAIN, President, American Society of Clinical Oncology: The studies like the one presented in "The New England Journal" are very dangerous for women. We already know that at least 25 percent, if not more, of women don't get mammography, and this could, with all the press surrounding it, make women less likely to get mammography, so I think it is dangerous.
BETTY ANN BOWSER: Oncologist Dr. Claudine Isaacs, head of the clinical breast cancer program at MedStar Georgetown University Hospital, thinks there are also risks to getting too much treatment.
DR. CLAUDINE ISAACS, MedStar Georgetown University Hospital: The risk of causing anxiety due to false positive screens, causing unnecessary procedures, like biopsies. But the one that I think doesn't get as much play is the risk of overdiagnosis, and that is really what this study was focusing on.
What is incumbent upon those of us in the scientific and medical community is to try and figure out which cancers are going to cause problems and which cancers are not. And we're not quite there yet. But we clearly have a job to do, and I think we're well on the way to at least trying to answer that question. We're not there yet.
BETTY ANN BOWSER: And until that day comes, women have little recourse, other than to read all they can on the subject and discuss it with a medical professional whose judgment they trust.
GWEN IFILL: There is much more on this story online, where you can find a breakdown of the debate and the data on mammograms and get commentary with scientific evidence from three leading physicians.