Sorting through the latest breast imaging options
From the October ACP Observer, copyright © 2006 by the American College of Physicians.
By Deborah Gesensway
When it comes to breast imaging, internists and family physicians are finding a new and often frustrating world.
Vast improvements in and improved access to imaging technology, such as MRI, ultrasound and PET scanning, have physicians and patients both asking if these should be ordered, and if so, for whom and when.
Constance Lehman, MD, PhD
Plus, a much-publicized study in last October's The New England Journal of Medicine concluded that digital mammography works much better than film mammography at detecting cancers in asymptomatic women who are younger, pre- or perimenopausal, or who have dense breasts. The problem is that only about 10% of all breast imaging facilities offer digital mammography.
To sort through the confusion, ACP Observer spoke with Constance Lehman, MD, PhD, one of the nation’s top breast imaging experts.
Dr. Lehman, section head of breast imaging at the University of Washington Medical Center—which has gone entirely digital—and the Seattle Cancer Care Alliance, discussed what physicians are doing wrong and current recommendations to help physicians better determine what to recommend to their patients, particularly as more and more women ask about their options.
Q: What is the biggest mistake physicians make?
A: Physicians sometimes confuse “screening” and “diagnosis” when making imaging choices, and the recommendations differ depending on what the imaging is for.
One of the worst scenarios—where women can end up having a delayed cancer diagnosis—happens when the patient and the doctor do not understand the difference between a workup for a patient who has symptoms and what is recommended for patients who do not have symptoms. The imaging we do for women with symptoms, such as a lump, is different than the imaging we do to screen women without symptoms.
Q: Is there still controversy over whether to start screening at age 40 or 50?
A: The data clearly show there is a benefit to screening women in their 40s. In fact, all major national organizations now agree that women should begin screening at age 40. I tell patients that not only do we know that breast cancer rates are increasing, but that the age of diagnosis is decreasing as well; another reason we don’t want women to wait until they are 50 to start being screened for breast cancer.
Q: Although mammography screening is sometimes recommended every one to two years, you say it should be done annually—particularly for younger women. Why?
A: Younger women have more aggressive and faster-growing cancers than older women. I would say to people, when there were debates about frequency, that if you are worried about the cost, I would much rather see a 70-year-old woman screened every two years rather than a 40-year-old, because a 40-year-old woman’s cancer is going to be growing faster.
Q: Should women with dense breast tissues undergo a breast ultrasound as well?
A: Breast ultrasound should never replace a mammogram, but only be used in conjunction with one, and generally only for women at increased risk and with dense breast tissue. At our center, we do not perform screening ultrasound, although we do use ultrasound routinely in women with palpable lumps. A large study is underway on the use of breast ultrasound for screening, and its results should answer more questions.
Q: What about using other imaging modalities to screen patients at average risk for developing breast cancer?
A: Sometimes physicians find themselves swayed by patient requests into ordering imaging that is not recommended for screening, such as ultrasounds or MRIs, because the patient wants something more and is willing to pay for it.
But for patients who are at average risk, we don’t recommend anything other than a regular clinical breast exam plus an annual mammogram starting at age 40. In fact, we strongly discourage them from having a screening ultrasound or screening MRI or screening PET. It’s a waste of money, we have no evidence that these tools will help women at average risk, and we are going to have many false positives.
Q: What about for women at high risk? New studies suggest that adding MRI as a complement, not as a replacement, to mammography can catch more early cancers.
A: These data are very compelling, but only for groups of women at very high risk, such as BRCA1/2 carriers or women with very strong family histories. This is not for women who say their grandmother had breast cancer at age 60.
Q: Are PET scans becoming part of the standard recommendation for imaging for diagnostic purposes?
A: The standard recommendation now is mammography plus ultrasound and biopsy if needed in women with suspicious lumps. There is no role for MRI in that population, and when we try to replace that workup with MRI or PET, we can make mistakes.
PET is a very exciting tool here, but it is almost completely under the umbrella of clinical trials, and I don’t think at his time there is any role for PET in screening or diagnosis. It does have a role in select patients with advanced breast cancer.
Q: Past studies showed that digital mammography worked better for premenopausal women, women on hormone replacement therapy and women with dense breast tissue. What is the effect of recent advancements?
A: Digital technology has significantly improved to the point where we feel it has improved for all our patients, not just for these three groups. This has stimulated a lot of people to say we should make sure that these women have access to that technology.
Q: But digital mammogram equipment is expensive and many third-party payers haven’t been willing to pay more for digital exams. How are mammography centers coping?
A: Sites are struggling. They can purchase four film units or one digital unit. It always feels awkward to say to a patient, "don’t worry, you’ll probably be fine."
Whole radiology departments have been entirely digital for years except for mammography because the resolution that we need to interpret a mammogram is much higher than the special resolution that we need to interpret a chest X-ray or MRI. We can read everything else on fairly standard monitors, but when we read our mammograms, we can’t use those same monitors. We need very high-resolution monitors.
The bottom line is that we are in a transition period. In the next 10 years, we will have significantly more access to digital technology, but right now we are not there.
Q: Should physicians send their patients to facilities offering digital mammography if it's an option?
A: Yes, but with the following caveats:
Just because a center has the latest and greatest technology doesn’t mean it provides the best service. Research the quality of the mammography centers in their areas; it can vary widely, and technology is only one component.
Make sure the center has well-trained technologists and radiologists who are either specialists in breast imaging or knowledgeable and experienced in mammography.
Ask if the center has American College of Radiology accreditation for its sterotactic biopsy, ultrasound-guided biopsy and breast ultrasound programs. Those three programs are voluntary, but if centers are really doing a lot of breast imaging and if they are serious about it, they’ve taken this extra step.
Q: What's the most important message for internists to give to patients they refer to a digital mammography center?
A: Go to a high-quality center that has experience, and a high-quality center doesn’t just mean the kind of equipment they have.
Personally, I would want to go to a specialist because I know a specialist is going to be aware of how to obtain the highest quality mammogram possible—whatever the technology—and how to interpret the findings.
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