Mammograms: Saving Lives?
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SUSAN DENTZER: For millions of American women, getting an annual mammogram to screen for breast cancer is a routine a part of preventive health care.
HEALTH CARE WORKER: “Relax your shoulder…Hold still for me…”
SUSAN DENTZER: But lately, the subject of mammography has been fraught with controversy.
Recently, Health and Human Services Secretary Tommy Thompson stepped in last week to reaffirm that the government came down firmly on the side of screening.
TOMMY THOMPSON, Secretary, Health & Human Services: When it comes to mammography, the federal government’s recommendation remains very clear: Women in their forties and older should be screened every one to two years with mammography.
SUSAN DENTZER: That’s been the standard recommendation for years of private groups like the American Cancer Society — as well as of federal agencies like the National Cancer Institute.
But Thompson and other federal officials have been forced to reiterate those recommendations because of recurring doubts about mammography. Some were raised again recently by two Danish researchers, Ole Olsen and Peter Goetzsche.
They conducted a highly technical analysis of medical studies that had tested the value of screening mammograms from the 1960s to the 1980s. Based on that analysis, they contended that the way many of those studies were conducted had been flawed.
In a January 2000 article in the prestigious British medical journal, “The Lancet,” they concluded that: “Screening for breast cancer with mammography is unjustified.”
Olsen and Goetzsche were hardly the first to raise questions about mammography — and to voice doubts that screening for breast cancer actually saves lives.
Another skeptic is Donald Berry, who chairs the Department of Biostatistics at the M.D. Anderson Cancer Center of the University of Texas.
DONALD BERRY, Chairman, MD Anderson Cancer Center, University of Texas: Unfortunately, we don’t know what the benefit of mammography is. If there is a benefit, that benefit is small.
SUSAN DENTZER: And Berry says that because mammography also carries risks — including modest amounts of radiation emitted by screening machines — the small benefits don’t seem worth it.
DONALD BERRY: If I were a woman, I would not get a mammogram. I’ve compared the benefits and the associated uncertainty in the benefits, and the associated uncertainty in the risk, and in my comparison of the two, I think it’s a slam dunk.
SUSAN DENTZER: On the opposite side are backers of screening like Dr. Claudia Henschke, a radiologist at Weill Cornell Medical College. Along with several colleagues, she challenged Olsen’s and Goetzsche’s analysis.
Henschke’s group found that, in one Swedish study, mammography produced a 55 percent drop in breast cancer deaths eight to eleven years after screening began.
DR. CLAUDIA HENSCHKE, Weill Cornell Medical College: Screening for breast cancer, for lung cancer, can really save more lives than anything that we’ve done in the past 30 years.
I think there’s also no dispute about that, that early, early detection can make a huge difference.
SUSAN DENTZER: To find out more about the pros and cons of mammography, we spoke to a range of people — from biostatistics experts like Berry, to women who’d battled breast cancer, like Katie Burney.
KATIE BURNEY: I love mammography. I would go and stand on the street corner and sell it, because it’s the only way it was discovered. It was very important in my case.
It was the only way you could find it.
SUSAN DENTZER: Burney was one of about 192,000 U.S. women diagnosed last year with breast cancer — a disease that, in 2001, also cost 40,000 American women their lives.
Cases like hers illustrate what Dr. Peter Greenwald of the National Cancer Institute says is the undisputed value of mammograms.
DR. PETER GREENWALD, National Cancer Institute: Mammography detects smaller cancers when you have more options for treatment, and everyone agrees with that.
We know from knowledge of cancer biology when tumors are small, before they’re vascular, and before the cells look more aggressive, more malignant, there may be a better chance of cure.
SUSAN DENTZER: At that early stage, women also have less drastic treatment options. Dr. Shawna Willey is chief breast surgeon at George Washington University Medical Center.
DR. SHAWNA WILLEY, George Washington University Medical Center: We know that if we can catch breast cancer at the earliest stage possible, not only are we improving a patient’s survival, we may also be limiting the kind of treatment or the aggressiveness of treatment they need.
SUSAN DENTZER: And that’s precisely what happened to Burney, who now attends a support group at George Washington for breast cancer survivors.
A routine mammogram first turned up tiny calcium deposits, like the ones pictured here, in one of her breasts. A subsequent biopsy of those deposits found cancer cells. But the cancer was still so small, and at such an early stage of development, that she was able to have a partial mastectomy that left much of her breast intact.
She could also forego other difficult treatment.
KATIE BURNEY: Having found cancer early has kept me from having to have chemotherapy or radiation, for which I’m inordinately grateful.
SUSAN DENTZER: Experts call these the “quality of life” benefits of mammography that make being a cancer patient a little less unpleasant.
But does mammography really produce even bigger benefits — actually preventing deaths from breast cancer and thus saving lives? Answering that question is far more difficult.
And that’s in part because of mammography’s known drawbacks.
SUSAN DENTZER: One of those is what’s called a “false negative.” Despite today’s highly sophisticated mammography equipment, in about one of seven cases where there actually is cancer present, a mammogram will fail to pick it up.
That’s what seven years ago to Kerry Dumbaugh, now 49, when her gynecologist found a small lump in her breast.
KERRY DUMBAUGH: I had just had a mammogram two days before, which was standard procedure, and then I took the films to Dr. Jerome, and she found a lump. The mammogram had been totally negative.
SUSAN DENTZER: A swift biopsy led to a diagnosis of breast cancer, followed by a lumpectomy and radiation.
SUSAN DENTZER: So do you — do you take mammograms seriously at this point?
KERRY DUMBAUGH: Oh, very seriously. I would never miss one, but I’m just not sure how to feel about them.
I guess my feeling would be that if you’re just relying on a mammogram by itself, based on my experience, you really may not be getting the whole story.
DR. SHAWNA WILLEY: And this is what I always tell patients, is statistics fall apart when you apply them to an individual.
So if you have a patient who mammography worked for, they’re big advocates of it.
There’s the other patients who had a malignancy that didn’t show up in mammography. They often feel betrayed by mammography. They feel that it doesn’t work.
SUSAN DENTZER: Then there’s another problem: So-called “false positives.” That’s when today’s highly sophisticated screening equipment spots small abnormalities that, at first glance, may or may not be cancer.
Women may be called back to undergo a second, more intensive screening examination — and may even have to undergo surgical biopsies of breast tissue that later turns out to be normal.
DONALD BERRY: A woman who has mammograms for the ten years of her forties, has a 55 percent chance of having at least one false positive.
During that period, the woman persuades herself that she has cancer and that she’s going to die of this disease. So it’s a very negative thing.
SUSAN DENTZER: But at least some women we spoke with disagreed with that.
Linda Tarr-Whelan, a colon cancer survivor, also had a breast cancer scare four years ago. Small calcium deposits called micro-calcifications were found in one breast.
LINDA TARR-WHELAN: They were found through mammography, and, and that was an important sort of thing. It was also very scary.
But it was all worth it in the end and not only because we would have caught something early if it was malignant, but, in fact, they were benign, which was the good news, and that was very important to someone who had had a different kind of cancer.
SUSAN DENTZER: There’s at least one other major area of doubt about mammography. Although mammograms enable abnormalities to be found earlier, it isn’t automatically true that this translates into saved lives.
That’s partly because not all cancers found by mammograms will turn out to be fatal in themselves.
A prime example is a condition known as DCIS, for Ductile Carcinoma In Situ.
DR. SHAWNA WILLEY: Ductile Carcinoma In Situ is the presence of cancer cells that are confined within the duct on a microscopic level.
So these are cells that have undergone malignant transformation but have not yet spread outside of the duct, so that they’re still contained within the duct. A synonymous term would be “non-invasive cancer.”
SUSAN DENTZER: In fact, some experts consider DCIS a pre-cancerous condition and refer to it as Stage Zero Cancer. The problem is that its course is unpredictable.
Dr. Rachel Brem, a radiologist and breast cancer survivor herself, directs breast imaging at George Washington.
DR. RACHEL BREM: We know that a third of Ductal Carcinoma In Situ go on to become the invasive form of the disease, the form that has the potential to spread to the nodes and metastasize.
But we don’t know which third will go on to become an invasive cancer, and therefore it’s important, it’s critical to treat each and every one as if it has the potential to become that invasive form of the disease.
SUSAN DENTZER: But Berry says that the other side of the coin is that mammograms that find DCIS can also lead to unnecessary treatment. That’s because many of those cases, if left undetected, would never have become invasive — and would not have killed the patient.
DONALD BERRY: I think the latest figures are something like 48,000 women per year are diagnosed with DCIS mammographically. Whereas, pre-mammograms, we had 4,000 or something like that.
These women, without mammograms, most of them would never know they had DCIS.
Is finding DCIS important? We don’t know. If it’s not important, than we probably shouldn’t be finding it.
SUSAN DENTZER: Despite all the controversy, a panel of experts that advises the government on preventive health care reported last week that the “weight of the evidence” still supports the value of mammograms.
And even skeptics like Berry concede that mammography may have played a role in a decade-long decline in the U.S. breast cancer death rate.
In the meantime, technology to detect breast cancer is changing rapidly, with recent entrants to the field like digital mammography and computer-aided detection. That could soon make a debate about the effectiveness of today’s mammography obsolete.
There’s also the prospect that future could help to eliminate some of today’s common problems, like false positives.
DR. PETER GREENWALD: We think there is a possibility that we could look at patterns of protein in the blood in order to distinguish breast cancer from pre-cancer, from benign breast disease, from normal. That’s a very exciting and important research area, which holds out promise for something better in the future.
SUSAN DENTZER: And one that also holds out the hope of banishing the shadow of breast cancer from even more women’s lives.