As reported by The New York Times, November 1, 2005.

Are Mammograms Right for Everyone?

By Deborah Franklin

Women who worry about getting breast cancer can take comfort in last week's news: based on a new analysis of nationwide data, one of mammography's most stubborn critics has changed his mind about its ultimate benefit as a screening test.

"The American Cancer Society has it right. I do think mammograms save lives," said Dr. Donald Berry, the chairman of biostatistics at M. D. Anderson Cancer Center in Houston and the chief author of a multicenter analysis of national breast cancer statistics, published Oct. 27 in The New England Journal of Medicine.

Dr. Berry and his colleagues conducted the study to remedy statistical soft spots in earlier research. They found that much of the 24 percent drop in deaths from breast cancer in the United States since 1990 could be attributed to widespread mammogram screening every year or so among women 40 and older. Advances in treatment also significantly helped bring the death rate down, he said, and proper follow-up treatment was crucial to the routine scan's benefit.

But is a mammogram - a filmed image produced by extremely low-dose X-rays - the best screening tool for everyone?

It is certainly not perfect, as Dr. Berry would be the first to point out. According to studies cited by the National Cancer Institute, 10 to 20 percent of breast cancers detected by a physical exam were missed by a film mammogram.

And even as Dr. Berry's new findings reinforce the traditional scan's overall value, some doctors have begun using other technologies - digital mammography, ultrasound and M.R.I. scanning ( or, as some doctors call it, M.R.) - to hunt for breast malignancies in some women.

Are these other tests better?

Not necessarily, according to Dr. Constance Lehman, a radiologist at the University of Washington, who is spearheading a large study of M.R.I.'s possible benefits for breast cancer patients.

Recently, Dr. Lehman has also been fielding phone calls from healthy women seeking the new test, including some who want to bypass traditional mammography. She urges them not to make that mistake.

"We have callers who say: 'I simply want the best tool. When can I schedule an M.R.I.?' " Dr. Lehman said. "Others say they had their usual mammogram screening last month, and it was clear, but now they want a digital mammogram, too, 'just in case.'

"It's very challenging, but we have to tell most, 'No, this is not the right tool for you.' "There's a lot of confusion out there."

Each test has its strengths and weaknesses, Dr. Lehman and other experts agree. And though film mammography is not perfect, none of the alternatives have yet been as thoroughly vetted in terms of lives saved.

Digital mammograms made a news splash in September when the National Cancer Institute released details of the Digital Mammographic Imaging Screening Trial, a $26 million study of 49,528 women at 33 sites in the United States.

The new technology was found to be better than film mammograms at detecting cancer among three groups of women: those with very dense breasts, as determined by their doctors; women under 50, whatever their breast density; and women of any age who were premenopausal or who had had at least one menstrual period within 12 months of the last mammogram.

For a woman getting either a traditional film mammogram or the digital version, the experience of the exam is the same: each breast is compressed by a machine between square plates, while a very low dose of radiation is passed through the tissue. The major difference comes in how the image is viewed and stored. Digital scans are stored in bits and bytes on a computer where, theoretically, they can be enhanced for contrast if necessary, or otherwise manipulated to improve the information provided.

Despite these theoretical benefits, women outside the specifically named groups experienced no advantage with digital scans. Film mammograms were just as good, or maybe even better for many women. And among women of every age, whatever their menopausal status or breast density, the risk of a false positive - turning up something that looked like cancer but was not - was the same for film and digital scans.

The message from the Digital Mammographic Imaging Screening Trial "is that women should now be asking their doctors if they have dense breasts, and if the answer is yes, or they fall into one of the other very specific groups, then digital is best," said Dr. Carolyn D. Runowicz, a gynecological oncologist at the University of Connecticut, who is the incoming president of the American Cancer Society and a 13-year survivor of breast cancer.

So far, only about 8 percent of the screening clinics in the United States are equipped can do digital exams, with most of those concentrated on the East and West Coasts. Dr. Runowicz said she thought those numbers were likely to climb now that the digital study's data were in, but it may take time before the new machines are prevalent. In the meantime, she said, it is more important that a woman over 40 get a good annual mammogram in a timely fashion than that she get a specific type of scan.

Dr. David Dershaw, a radiologist at Memorial Sloan-Kettering who evaluated the digital mammographic study in an editorial in the same journal, said the experience and skill of the technician conducting the exam and the expertise of the doctor evaluating it were at least as crucial as whether the mammogram was digital or film.

"Most women are not going to have a choice about the machine, and that's O.K.," Dr. Dershaw said in an interview. "Don't make yourself nuts trying to find a center with a digital machine." As a basic rule of thumb, he said, centers that do 10,000 or 20,000 mammograms a year are probably better than offices that only do 1,000 or 2,000 annually.

Dr. Runowicz added that any woman who decides to switch screening clinics when she has her next annual exam should be sure to pick up all her previous films and take them along to the new appointment.

"The history of how your breasts have changed over time is very important," she said. "A woman could actually harm herself by switching to a new place unless she takes her old mammograms with her."

Some women and doctors are starting to look beyond mammograms, and not always for the better. Dr. Lehman said that some of the phone calls that worried her most were from women who said that they had refused mammograms to avoid the discomfort or the radiation, and that they wanted to be screened with ultrasound instead.

An ultrasound exam, also called a sonogram, uses sound waves to find breast abnormalities. Many breast specialists find it helpful at times as a relatively inexpensive follow-up to a mammogram to discern harmless cysts from more malevolent lumps, or for exploring dense tissue that looks opaque in an X-ray.

Dr. Wendie Berg, a radiologist at Johns Hopkins, is now enrolling 2,800 women in a carefully controlled multicenter clinical trial to determine more precisely how an added sonogram compares to a mammogram alone, especially for younger women with dense breasts or for women at high risk for breast cancer.

But Dr. Lehman and others worry that some women and their doctors may jump ahead of the evidence and rely on ultrasound alone. The expertise of the person performing this technique is particularly crucial to its accuracy, she said, and if it is used as a screening tool independently of a mammogram, ultrasound is more likely to turn up an unacceptably high number of spots that look suspicious and require biopsy but turn out not to be cancer.

Even more worrisome, sonograms cannot detect the tiny calcifications in breast tissue that can be the first signs of malignancy. Dr. Daniel C. Sullivan, head of the National Cancer Institute's Cancer Imaging Program, said that at least until Dr. Berg's clinical trial is complete, "the current advice is that ultrasound is not a useful screening tool."

At least one more technique shows promise in being able to detect tiny cancers that mammograms miss. M.R.I. uses a large magnet to track blood flow through the breast as a way of discerning malignant tissue from healthy tissue. Its main advantage is that it seems to be an extremely sensitive cancer detector. "If you have a negative M.R., that's a very good sign," Dr. Sullivan said.

But there are downsides here, too.

First, doctors say that M.R.I. is an even more sensitive test than ultrasound, and if used as a first-pass screening tool among women of average risk it would probably turn up a very high rate of false-positive results. That could lead to many needless biopsies, not to mention needless anxiety.

Also, unlike a mammogram, an M.R.I. scan requires the injection of an intravenous contrast agent to work. Finally, M.R.I. scans are much more expensive than the other screening technologies. According to the American College of Radiology, the average Medicare reimbursement for an M.R.I. scan of one breast is $781.83, compared with $85.65 for a film mammogram, and $135.29 for the digital version. The average reimbursement for a sonogram of one breast is $70.

Instead of using M.R.I. for widespread screening, most experts envision the technique as a supplement to mammograms that may prove most useful for monitoring women who have a combination of factors that that put them at much higher than average risk for developing a malignant breast tumor. These factors include, for example, carrying one of the genetic mutations that has been linked to breast cancer, having an especially strong family history or being a breast cancer survivor.

"Eventually," Dr. Lehman said, "maybe we will find out that women with dense breasts will also do better with an M.R. screening. But we don't have that evidence now, and we don't recommend it."