April 10, 2008
In Shift to Digital, More Repeat Mammograms
By DENISE GRADY
It is a phone call that women dread. Something is not quite right on the mammogram: come back for another one. But don’t worry, the script goes — most repeat tests wind up normal.
Still, most women know someone who has breast cancer, and even the calmest, most rational minds may think the worst when summoned back to the clinic.
At many centers, these nerve-racking calls are on the rise, at least temporarily — the price of progress as more and more radiologists switch from traditional X-ray film to digital mammograms, in which the X-ray images are displayed on a computer monitor. Digital is growing fast: in the United States, 32 percent of mammography clinics now have at least one digital machine, up from only 10 percent two years ago. Eventually, film will be phased out.
The rush to digital is occurring in part because for certain women — younger ones and others with dense breast tissue — it is better than film at finding tumors. Digital is especially good at picking up tiny calcium deposits, or calcifications, which are sometimes — but by no means always — a sign of cancer. In the long run, radiologists say, digital technology will make mammograms more accurate for many women.
But problems can arise during the transition period, while doctors learn to interpret digital mammograms and compare them to patients’ previous X-ray films. Comparing past and present to look for changes is an essential part of reading mammograms. But the digital and film versions can sometimes be hard to reconcile, and radiologists who are retraining their eyes and minds may be more likely to play it safe by requesting additional X-rays — and sometimes ultrasound exams and even biopsies — in women who turn out not to have breast cancer.
There have been no studies yet to measure what happens during this transition period, but many radiologists say they do find themselves calling more women back. About 35.8 million mammograms a year are done in the United States, including those for screening and follow-ups for problems. The National Cancer Institute recommends mammograms every year or two for most women over 40 (women at high risk may be advised to start earlier). Mammography is not perfect — it can miss tumors — but even its critics say it has helped to lower death rates from breast cancer, which is the second leading cause of cancer deaths in women, after lung cancer.
There are about 178,000 new cases of breast cancer each year in the United States, and 40,000 deaths.
Of 10 radiologists interviewed for this article, eight said that during the transition from film to digital, recall rates went up in women who were ultimately found to have nothing wrong. Normally a recall rate of 10 percent or less is considered desirable. But during the transition period at their clinics, the doctors estimated that callbacks of women who turned out to be healthy increased by a few percentage points to as many as 10. Only one radiologist reported no problems: Dr. Etta D. Pisano, a professor of radiology and biomedical engineering at the University of North Carolina, Chapel Hill.
“I don’t believe it,” Dr. Pisano said. “I question that there’s a problem with the transition.”
But Dr. Mary Mahoney, a professor of radiology and the director of breast imaging at the University of Cincinnati Medical Center, said, “I am living through the pain of this transition period on a daily basis.”
Her center recently opened an entirely digital clinic for breast cancer screening. “Our whole group is kind of pulling our hair out some days,” she said. “You struggle and you struggle. It’s just so much harder. These are really experienced, qualified radiologists who are wringing their hands. It’s where the increase in callbacks and biopsies is coming into play. It happens every day. Many times we’re able to bring the woman back, do additional views and feel comfortable we can follow that area.”
Regarding the higher callback rates, she said: “I know it’s not a small thing, the anxiety. Patients are practically in tears because they’re so worried. But I think in the long run it’s going to be to everybody’s benefit.”
Dr. Margarita Zuley, the director of breast imaging at the University of Pittsburgh Medical Center’s Magee-Women’s Hospital, said it can take six months to a year to learn to interpret the new images.
Lecturing in Manhattan recently about the transition to digital, Dr. Zuley told an audience of radiologists: “When you first start out, you may feel a little anxious and recall more patients because everything looks like a cancer to you. It’s O.K. Just bring the patients back. It’s part of the learning curve.”
Regarding higher recall rates during the transition, Dr. Zuley said: “Everybody sort of knows it, but it’s anecdotal. There are no numbers.”
Meanwhile, patients or their insurers are paying for the extra tests. Fees for mammograms vary around the country. A clinic in Manhattan recently billed an insurer $387 for a digital mammogram and then $336 for extra images of one breast — needed because of confusion between the old films and the new digital pictures — and was paid about half of those fees. Fees for film-based mammograms are usually $45 to $120 less.
Nancy Liber, a radiologic technologist at Dr. Mahoney’s center, was called back by her own colleagues at the center after her mammogram last month.
“I thought exactly what every woman does,” Ms. Liber said. “Immediately you panic and think, ‘Oh my gosh, what if something is really wrong?’ ”
She found herself worrying about what would happen if she became ill and unable to take care of her children. She did not even tell her husband what had happened until after the second test, which turned out normal. The concerns were due entirely to the difference between film and digital images. Despite the stressful experience, Ms. Liber said that from what she has seen in her work, digital mammograms are the way to go.
“The inconvenience it may cause is worth it,” she said. But, she added, “I definitely know what these women are going through.”
Radiologists say one of digital’s advantages is that it lets them adjust features like contrast and magnification, and see things that were blurry or maybe even invisible on film. In the long run, doctors say, the increased clarity of digital mammograms may lead to fewer healthy women being called back for more X-rays — but it takes time to learn the ropes.
Dr. Constance D. Lehman, the director of breast imaging and a professor of radiology at the University of Washington, said she was not sure whether more women were called back during the transition. But describing the two technologies, she said, “In some areas it’s like comparing apples and oranges.”
When looking at a woman’s first digital image, Dr. Lehman said, radiologists must ask themselves whether an apparent change in the breast is truly new, or was there all along but just not visible with earlier techniques.
Once a woman has had enough digital mammograms, the comparisons should be easier, radiologists say. But the first few may raise questions, because when radiologists compare, they often go back to images from two or three years before. And in some clinics that have a mixture of film and digital machines, if a woman is switched between the two types from year to year, ambiguities may crop up again and again. Many women do not know the difference between film and digital, or notice which is being used, and clinics may or may not inform them of potential problems during the changeover.
Digital mammography got a boost from a large study in 2005 that showed it was better than film at finding tumors in women under 50, or women of any age who had dense breasts, meaning a lot of glandular and connective tissue in proportion to fat.
A buzz grew around digital after the study. Some radiologists use the technology as a selling point, and others feel they must follow suit. Now, there is such a demand for digital machines that there is a six-month wait for certain types, Dr. Zuley said, even though they cost $350,000 to $600,000, about three to five times as much as units that use film.
Dr. Leonard M. Glassman, who practices at Washington Radiology Associates, said that his practice in the Washington, D.C., area, which performs 85,000 mammograms a year, converted to digital about two years ago.
“There’s an increase in the rate of things you think are abnormal for about three months, and then you get used to it,” Dr. Glassman said. “You take more extra pictures, of things that six months later you would dismiss. It happened probably 5 to 10 percent of the time right at the beginning, so it’s a significant amount, and then it tails off.”
When questions first arise, Dr. Glassman said, he does not warn women that the imaging may be the culprit, because he cannot be sure what the problem is until he sees the second set of X-rays.
“At the end I tell patients, ‘You were a victim of technology,’ ” he said. “They give me a blank stare. I say: ‘Your last one was film, this one was digital. They look different, and we just didn’t know that.’ ”