CHICAGO—Breast-cancer screening took center stage here at the Radiological Society of North American Scientific Assembly and Annual Meeting. New research showed that elastography—a technique that measures the stiffness of lesions—may help to reduce the number of unnecessary biopsies in women with breast cancer. Another study suggested that targeted breast ultrasound may obviate the need for biopsies in some women under 40, while other work suggested that ultrasound and MRI can help improve the detection of early-stage breast cancers.
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Not all the news was good, though: Others researchers cautioned that regular mammograms may increase the odds that very young, high-risk women will develop breast cancer, and, not surprisingly, radiologists also took the opportunity to attack the US Preventive Services Task Force (USPSTF) guidelines that recommend that the decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.
Here is a roundup of the news:
Adding elastography to breast ultrasound may help distinguish between cancerous and benign breast lesions, potentially reducing unnecessary biopsies, researchers reported. Used in conjunction with breast ultrasound, elastography correctly identified 98% of cancerous lesions and 78% of benign lesions in a study of 193 women.
“With more research, elastography could impact decisions to not perform biopsies in patients who don't need them, reducing anxiety and costs,” said Stamatia V. Destounis, MD, a diagnostic radiologist at Elizabeth Wende Breast Care in Rochester, NY.
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About 80% of breast lesions that are biopsied turn out to be benign, she said, quoting American Cancer Society statistics.
Elastography uses pressure from breathing, heartbeat, or pushing on the skin to examine the compressibility of a lesion.
“A malignant tumor will be stiffer than the surrounding normal breast tissue,” while a benign lesion will compress more and look smaller on a scan, she explained. All that's needed is special software and pushing a button on the ultrasound unit.
In a second elastography study, high-frequency ultrasound combined with the technique successfully differentiated among a variety of benign and malignant skin lesions.
Mary C. Mahoney, MD, Director of Breast Imaging at the University of Cincinnati Medical Center and Vice Chair of the RSNA Public Information Committee, said that elastography is not new, but is experiencing somewhat of a comeback due to improvements in the software.
“The equipment is relatively commonly available, as is the software,” but is increasingly being used for other conditions as well, including the detection of liver and thyroid malignancies, she added.
Targeted breast ultrasound of suspicious tissue may offer an alternative to biopsy for women under 40, other research suggests.
The technique correctly distinguished between cancerous and benign lesions in the majority of cases, reported Constance D. Lehman, MD, PhD, Professor and Vice Chair of Radiology at the University of Washington and Director of Imaging at the Seattle Cancer Care Alliance.
Dr. Lehman and colleagues retrospectively reviewed all breast ultrasound examinations performed at their facility between 2002 and 2006 in two separate analyses. The first study was designed to determine the accuracy of ultrasound as a primary diagnostic modality in women under age 30 with breast lumps. A total of 1,091 lesions were examined in 830 women.
Ultrasound proved to have 100% sensitivity for correctly identifying those lesions that were cancerous, Dr. Lehman said. The specificity of the test was 79.3%.
The second study involved examination of 1,327 palpable masses in 1,032 women age 30 to 39.
Again, all lesions were correctly detected by ultrasound, corresponding to 100% sensitivity. The test's specificity of the diagnostic test was again lower—89%.
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The lower specificity rate precludes ultrasound from being used as a screening tool, but “it's a fantastic tool in the diagnostic setting,” she said.
RSNA spokesperson Joseph Tashjian, MD, President of St. Paul Radiology, said the findings support “what we have seen at our institution—Ultrasound reliably answers the question as to whether the lesion is cancer or normal breast tissue.”
Ultrasound, MRI for High-Risk Women
Other researchers found that adding ultrasound and/or MRI to annual mammograms significantly improved the detection of early-stage breast cancer in women who are at high risk for the disease.
Screening with mammography and physician-performed ultrasound, performed annually for three years, detected 29% more cancers and 34% more invasive cancers than mammography alone, said Wendie A. Berg, MD, PhD, a breast imaging specialist at American Radiology Services-Johns Hopkins at Green Spring Station in Lutherville, MD.
The study involved 2,809 women at increased risk for breast cancer. All had dense breasts, 53% had a personal history of breast cancer, and 1% were BRCA mutation carriers.
Combined screening with mammography plus ultrasound detected 82% of the cancers, compared with only 53% for mammography alone, Dr. Berg reported. “Importantly, most of the cancers that we found with ultrasound were the small invasive cancers that are likely to spread and could ultimately kill.”
A subset of 612 patients were screened with MRI in the third year of the study. “MRI increased the cancer detection rate by another 56% in that subgroup of patients, and increased the detection of invasive cancers by 67%,” Dr. Berg said.
“Our recommendation is that women continue their annual mammography, and if they're high risk, they should have an additional MRI. If they can't tolerate an MRI, ultrasound is a reasonable alternative.”
Again, the findings show “a real advantage with ultrasound,” Dr. Tashjian said. “MRI had even better results,” but it has certain drawbacks—chiefly, a high cost that is not always covered by insurance, administration of a contrast agent, and a tendency to make some patients feel claustrophobic, he said.
Warning about Mammograms & Chest X-rays in Very Young Women Already at High Risk
Other researchers cautioned that having mammography or chest x-rays may increase the risk of breast cancer in young women already at high risk of the disease.
The researchers performed a meta-analysis of six studies that looked at the effect of exposure to low-dose radiation on 9,420 women at high risk of breast cancer.
Results showed that high-risk women who had five or more mammograms or chest x-rays before age 20 were two-and-one-half times more likely to develop breast cancer than were high-risk women who were not exposed to low-dose radiation.
Women, especially those under 30 who are already at high risk of breast cancer due to genetic mutations or a family history of breast cancer, may want to consider other screening methods such as MRI that do not involve exposure to radiation, concluded Marijke C. Jansen-van der Weide, PhD, an epidemiologist in the Department of Epidemiology and Radiology at University Medical Center Groningen in the Netherlands.
If alternative screening methods are not available, she recommended having mammograms every other year, starting at age 30.
Asked to comment on the findings, Dr. Mahoney stressed that they do not apply to the general population. In fact, the results apply to only a very small number of breast cancer patients–only 5% of all breast cancers, she said.
USPSTF Guidelines Blasted
At a special news briefing, a panel of breast-screening experts said they were perplexed by the newly revised USPSTF that recommend against routine mammography screening for women in their 40s—or more precisely, that the decision to start regular, biennial screening mammography before age 50 should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms. The Task Force also recommends that women age 50 to 74 have mammograms every two years instead of every year.
“The net effect of the new guidelines is that screening would begin too late and its effects would be too little. We would save money, but lose lives,” said Stephen A. Feig, MD, Professor of Radiology at the University of California at Irvine and President-Elect of the American Society of Breast Imaging.
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The breast-screening panel at the meeting said that the guidelines would represent a major setback, wiping out decades of progress. “Deaths from breast cancer have dropped by 30% since 1990 when mammography screening beginning at age 40 became more widespread,” said Daniel B. Kopans, MD, Professor of Radiology at Harvard Medical School and Senior Radiologist in the Breast Imaging Division at Massachusetts General Hospital, who contended that the task force relied on studies with methodology flaws that underestimated the benefits of mammography.
He and his copanelists also took issue with the Task Force's concerns about false positives—concerns that the panel said weighed heavily on the decision not to recommend screens for younger women.
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“You're going to have some false positives, if you detect cancer early,” when it is most curable, said Dr. Feig, who also discounted concerns about radiation exposure: “The risk is negligible compared with the benefits of screening,” he said.
The breast-screening panel said it supports the American Cancer Society guidelines, which continue to recommend annual routine mammography screening for all healthy women age 40 and over. “Current American Cancer Society guidelines have been shown to save lives,” Dr. Kopans said. “The Task Force, by its own admission, said women will lose their lives. That doesn't seem to be much of a choice.”
Dr. Kopans said he thinks the government panel had “good intentions,” but that there were no radiologists on the panel.
At a House Energy and Commerce Subcommittee on Health hearing in Washington, DC, Diana Petitti, MD, MPH, Vice Chair of the USPSTF, said that while no radiologists were on the task force, they were “consulted and reviewed the recommendations and provided input.”
Her comment about the implications of the guidelines for younger women is also now posted on the Task Force's Web site: “So, what does this mean if you are a woman in your 40s? You should talk to your doctor and make an informed decision about whether mammography is right for you based on your family history, general health, and personal values.”
© 2010 Lippincott Williams & Wilkins, Inc.