The Future of Breast Cancer Screening

An array of high-tech detection techniques and devices is on the scientific horizon.

From the WebMD Archives

Cora's doctor found a tiny growth in her right breast when she was 55 years old. To determine whether it was cancer, he inserted a small tube inside her nipple to extract cells for study under a microscope.

The results were inadequate, so he asked her to come in for another visit. This time, she was given anesthesia so he could surgically remove the suspicious tissue for examination.

Much to Cora's relief, the lump turned out to be benign, but recalling the whole process is enough to make the now 61-year-old tax auditor cringe.

"The nipple thing was very painful," she says, associating the unpleasant experience with other cancer-screening procedures she considers torturous, such as the mammogram, which involves placing one breast at a time on a cold device then flattened for filming.

Still, to this day, Cora, much like many of her peers, diligently subjects herself to such tests. Why?

Many shake it off as a small sacrifice for peace of mind. After all, women have a one in eight lifetime risk of developing breast cancer. The disease is the second leading cause of cancer death in females after lung cancer.

Yet medical visionaries are hoping women won't have to be martyrs for long. While mammography is still widely regarded as the gold standard for detecting malignancies, an array of new or improved technologies is now on the horizon -- using magnets, electricity, sound waves, and cellular biology as screening tools.

Some methods promise to make breast cancer screening more comfortable for women. A number pledge greater accuracy and fewer false positives. Still others are whispered to be borne out of entrepreneurial motivations. Doctors dream of someday being able to take a simple blood test to learn if a woman has breast cancer, or will develop it in the future. Some even hope tests will let them tell a woman when she will likely develop breast cancer, and what can be done about it.

But word on the scientific street is that such diagnostic wizardry will not be available anytime soon. What can you do in the near future? Here are newly improved or experimental screening techniques that may help you screen for breast cancer soon.

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Improving Familiar Devices

The mammogram is the best tool for breast cancer screening at the moment. With about 85% accuracy, the X-ray device has spotted even malignancies that are too small to touch, ultimately saving many women from suffering and death.

But there's always room for improvement, and several groups are in hot pursuit of the next major screening method for breast cancer.

Digitial Mammography

Digital mammography, which takes the X-ray image on computer rather than on film, is gradually becoming available. There are now about 300 such units in use around the country, according to the American Cancer Society.

The instrument "offers enormous potential" because the pictures can be manipulated, says Robert A. Smith, PhD, head of screening at the American Cancer Society.

Much like digital photographs currently taken by consumer digital cameras, breast images taken by digital mammography can be magnified, and the resolution can be adjusted to get a clearer picture.

While easier to use, digital mammography is not more successful at finding cancers than traditional mammograms -- and the cost of each machine tends to be prohibitive.

Computer-Aided Detection Devices (CAD)

Smith says the digital imaging technology could especially improve with better-programmed computer-aided detection (CAD) devices, which are now used by some labs to analyze standard mammograms and act as second-opinion readers for radiologists.

Early tests show CAD can help point out cancers otherwise missed by experts. Yet there is an ongoing debate about whether a machine can sufficiently replace a second radiologist in reviewing test results.

Ultrasound

Medical experts who want to evaluate problems first found during a mammogram or a physical exam often turn to ultrasound technology. An ultrasound device releases sound waves into the body, and creates a picture of the breast from the bouncing back of the waves. The idea is that sound echoes differently of off masses of various consistencies, such as fluid-filled cysts, solid tumors, or normal tissue.

Ultrasound has been around for decades, but improvements to the technology promise to make it more helpful in looking for cancer. One advance of note is still in the experimental stages: an ultrasound that takes 3-D images of the breast as opposed to 2-D ones.

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MRI

Another breast detection technique that scientists have gradually enhanced over the years is magnetic resonance imaging (MRI). In this method, a large magnet, radio waves, and a computer work together to produce what experts consider a very clear, cross-sectional picture of the breast. Furthermore, experts can examine specific areas by injecting a dye in the veins, which collects in problematic tissues, making them more visible in the MRI picture.

Similar techniques are now under investigation, such as magnetic resonance elastography (MRE), which draws an image of the breast based on the elasticity of vibrating tissue.

Toward a Better Image (of Breasts)

Many methods to check for breast cancer are still experimental right now. Often, women at high risk of developing the disease turn to clinical trials of these imaging devices in an effort to ease their concerns.

Some of these experimental methods are:

  • Positron emission tomography (PET). This technology makes use of the notion that a tumor has a higher metabolism than normal tissue. When a radioactive substance is injected into a patient's vein, it travels to rapidly dividing cancerous cells, which have greater nutrient needs. Ideally, a PET scanner would detect the activity and produce an image of it.

  • Ductal lavage and ductoscopy. The idea behind these two methods is that certain cancers begin in the milk ducts of the breasts. In ductal lavage, a catheter is inserted through the nipple and into the milk ducts. A saline solution is emptied into the ducts, and then withdrawn. Then the cells washed out from the ducts are checked under a microscope. In ductoscopy, a catheter with a light at the tip is inserted through the nipple into the ducts and a dye is injected. The dye outlines the shape of the duct and an X-ray ideally shows whether there is an abnormal growth in the area.

  • Electrical impedance spectral imaging (EIS). Low-frequency electrical currents are applied to the breast, and an image is formed based on the theory that normal tissue and cancerous masses conduct electricity in different ways.

  • Microwave imaging spectroscopy (MIS). This device uses microwave energy that is similar to cell phone frequencies (but at a much lower level). The technique is particularly sensitive to water, and can detect areas where there is more of it. Tumors are thought to have more water and blood than regular tissue.

  • Near infrared (NIR) spectral imaging. This method is based on the idea that infrared light is sensitive to blood, creating an image of hemoglobin inside the breast. Knowledge of vascular activity is believed to help spot early tumor growth, and determine its stage.

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Researchers at Dartmouth College in New Hampshire are simultaneously studying four of these screening techniques: NIR, MIS, EIS, and MRE. If one or more of these methods are found to be promising, scientists might look into integrating the technologies into a single tool.

"We're excited about the possibilities, but there's a lot to be worked out," says Keith Paulsen, PhD, principal investigator of Dartmouth's Breast Imaging Project.

Clinical trials began April 2003, and may wrap up next summer. An interim analysis with official statistics on the success of each technique is due in the next couple of weeks; meantime, Paulsen is optimistic. "The projects are going well," he says.

Looking Into a Biological Crystal Ball

Several studies are currently looking into the possibility of diagnosing breast cancer at the cellular level. There is hope that someday researchers will be able to identify a turning point when biological substances become cancerous, thus leading to development of methods for detecting warning signals.

The National Cancer Institute alone has funded research into at least a half-dozen tests that involve examining typical and irregular proteins, molecules, genes, and other biological matter. One such large clinical trial in progress is a blood test. By analyzing concealed patterns of protein in blood, investigators propose being able to distinguish malignant tissues from benign ones.

Although this blood test is currently being tested only for ovarian cancer, researchers are hopeful the technology, once proven, could be adapted to other cancers. If everything goes well, investigators plan to compare the outcome of the trial with other blood test research around the country of other cancers.

One such study to detect breast cancer by looking at blood cells has already ended. The results? The blood test was 95% successful in spotting malignancies. The complete report is currently being reviewed for publication in a medical journal.

"Everything looks extremely exciting...but we want to move cautiously," says Lance Liotta, MD, PhD, a principal investigator of the Clinical Proteomics Program, and chief of the laboratory of pathology at the National Cancer Institute.

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When could such a blood test become available? Liotta says that depends on three factors:

  • First, researchers must check the accuracy of the blood test by waiting to see if women develop cancer.
  • Second, those results must prove the test works reliably in large groups of women.
  • Third, the Food and Drug Administration must approve the test.

If all variables fall into place, however, he says the test could be on the market within the next 5 years -- unless competing private companies come up with the technology first.

How Better Screening Helps High-Risk Women

The technology to screen for genetic mutations is already available, but it is recommended only for women who have reason to believe they are at high risk for developing breast cancer, such as a strong family history.

In the early 1990s, it was found that women with certain mutated genes -- BRCA1 and BRCA2 -- tend to have a 50% to 85% risk of developing breast cancer.

Since then, the issue of genetic testing has been controversial. Some people say the presence of the mutated gene does not necessarily mean a woman will develop breast cancer, so a positive result could cause unwarranted concern. Plus, these genes account for relatively few cases of breast cancer. Also, there is fear that insurance companies and employers could discriminate against women who have the mutation.

Women who do decide to go through with genetic testing are advised to first undergo genetic counseling to help them deal with the information, and decide what to do about it.

Better technology for early detection could help women at high risk tremendously, says Judy Garber, MD, director of cancer risk and prevention at the Dana-Farber Cancer Institute.

"Instead of deciding at 30 to have your breasts removed because you might get breast cancer sometime in the next 50 years, maybe you could wait until you're 60, after you've had your children and you've gone through your life."

WebMD Feature Reviewed by Charlotte E. Grayson Mathis, MD

Sources

SOURCES: American Cancer Society. Robert A. Smith, PhD, American Cancer Society director of cancer screening. Keith Paulsen, PhD, principal investigator of Dartmouth's Breast Imaging Project. National Cancer Institute. Lance Liotta, MD, PhD, a principal investigator of the Clinical Proteomics Program, and chief of the laboratory of pathology at the National Cancer Institute. Judy Garber, MD, director of cancer risk and prevention at the Dana-Farber Cancer Institute.

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