Newer ways to diagnose breast cancer

October is National Breast Cancer Awareness Month, and every year at this time, we’re reminded that the Philippines has the highest incidence of breast cancer in Southeast Asia, about 48 per 100,000 Filipino women, and that the average Filipina faces a 10-percent risk of getting it. Some 6,360 breast cancer patients die each year in the country, making it the single leading cause of death among Filipinas.

But we’ve also been getting some good news. More women are surviving — not only because of advances in treatment, but also because the disease is detected early, while it can still be cured. Researchers are discovering new ways to detect breast cancer in its earliest stages, when it is easier to treat. “For initial screening, the mammogram is still the gold standard,” says Rache Simmons, MD, a surgical oncologist at the Iris Cantor Women’s Health Center in New York. The American Cancer Society (ACS) recommends a yearly mammogram for most women starting at age 40.

Mammography, however, is not perfect: It may not detect up to 20 percent of breast cancers (particularly if a woman’s breasts are dense). “Mammography is also very operator-dependent,” says Carol Ann Diamond, MD, a medical oncologist at the Mount Sinai School of Medicine in New York. It means that the accuracy of the results is dependent on the technician performing the exam and the radiologist reading the films. In addition, many women are deterred from undergoing the procedure because they perceive it to be uncomfortable and awkward.

New screening tools, such as digital mammography and magnetic resonance imaging (MRI), are helping doctors spot breast cancer sooner. “Many new technologies and techniques are out there and are being touted as promising, but not all have been shown to be valid,” says Alisan Goldfarb, MD, a breast surgeon also at Mount Sinai.

Here is a guide to some of the newer breast cancer imaging techniques available:

Digital Mammography

“Digital mammography is the wave of the future for breast cancer screening,” says Dr. Goldfarb. Digital mammography differs from regular mammography in that it takes the x-ray image on computer rather than on film. Much like a basic digital photograph, breast images taken by digital mammography can be magnified and the resolution can be adjusted to give the radiologist a clearer picture of the breast. Digital mammography, compared to regular mammography, appears to be better at finding cancers in women with dense breast tissue, which is common in younger women.

The digital mammographic imaging screening trial compared digital and traditional mammograms of almost 50,000 women. Analysis showed that digital mammography was better at detecting tumors in women under 50, in pre- or perimenopausal women, and in women with dense breasts. However, women over 50, who had stopped menstruating completely, and who didn’t have dense breast tissue, gained no advantage.

Digital mammography is available in the Philippines at the Cardinal Santos Medical Center and St. Luke’s Medical Center.

Ultrasound

“Ultrasound is another extremely helpful tool,” says Nagi Khouri, MD, director of breast imaging at Johns Hopkins Avon Foundation Breast Center. “Although ultrasound is only as good as the doctor performing it, and is the most frequently used test to get more information about a nodule already identified as suspicious on a mammogram, it can sometimes pick up small abnormalities in the dense areas of breasts which mammography might miss,” adds Dr. Goldfarb.

Ultrasound testing uses sound waves to create an image of the breast and is especially useful also for women with dense breast tissue.

Computer-Aided Detection

Another technological advance that allows improved evaluation of suspicious findings detected by mammography, is the use of computer programs to examine X-rays. This process is called computer-aided detection (CAD).

In traditional mammography, your X-rays are reviewed by a radiologist, whose skill and experience play a large part in determining the accuracy of test results. In CAD, a computer scans your mammogram after a radiologist has reviewed it and flags suspicious areas. While many of the flagged areas may prove to be harmless, using mammography and CAD together can help doctors better identify suspicious tumors.

But a 2007 survey of data from over 400,000 mammograms, published in the New England Journal of Medicine, found that CAD increased false-positive results without improving detection of invasive breast cancer. Dr. Khouri says, “In my experience, CAD can be useful, but it’s not a replacement for a radiologist. The more experienced the radiologist, the less he/she will need CAD.”

Magnetic Resonance Imaging (MRI)

In March last year, the ACS recommended that women with very high risk for breast cancer should be screened annually with an MRI as well as a mammogram. An MRI is recommended in addition to a mammogram for women with a lifetime risk of breast cancer of 20 percent or greater. Factors that can put you at high lifetime risk include:

• Strong family history of breast cancer (multiple relatives who have had breast cancer, particularly a mother or a sister).

• A mutation in the BRCA 1 or BRCA 2 gene or a parent, child, or sibling with a mutated BRCA 1 or BRCA 2 gene. 

• Hormonal, menstrual, and childbirth histories and results of previous biopsy may suggest a higher risk.

• Radiation treatment to the chest for Hodgkin’s disease between the ages of 10 and 30.

It is the first time the cancer society has urged the use of MRI — which detects the tiniest tumors — for breast cancer screening, in addition to mammograms. “One truth about breast cancer is that when it’s detected early, we can cure it,” said Connie Lehman, director of breast imaging at the Seattle Cancer Care Alliance and a member of the expert panel which recommended the use of MRI. “Mammograms are a great tool, but they are imperfect. MRI has been established as a great complement to mammograms.”

In 2003, the cancer society issued guidelines that stopped short of recommending MRIs for women at high risk for the disease. “More research evidence on MI effectiveness now warrants it,” the society said.

Given the impressive ability to detect tumors not found on mammograms (see photo), MRI might seem to be a logical choice for breast cancer screening across the board. Yet, the ACS is not recommending it for women at average risk. There are several important reasons for this:

• MRI has about a 10-percent false-positive rate, about twice the rate of mammograms. False positives can lead to unnecessary biopsies and worry on the part of patients.

• It can be stressful. The procedure requires a substantial investment in time and fortitude also on the part of the patient.

• Mammography is getting better all the time. High-quality mammography can be found in most major medical centers and digital mammography is now available in a few hospitals.

• The radiation risk of mammography is very small. There’s less than a one-in-a-million chance it will cause a radiation-induced cancer.

• MRI has limitations — and limited availability. (High-quality breast MRI is still unavailable in many parts of the Philippines.) Moreover, breast MRI can’t be performed on women who have certain devices in place, such as pacemakers.

• It’s expensive and many health insurance companies and HMOs won’t pay for it. At about P8,000, breast MRI costs about eight to 10 times as much as a mammography.

But Dr Lehman says there is now no question that MRI use can save the lives of many high-risk women by catching cancers earlier. “We know what happens when they are left untreated,” she said.

For most women over age 40, however, getting an annual mammogram and clinical breast exam is still the best way to catch early-stage, highly-treatable cancers. So don’t forget to make — and keep — that annual appointment. It may save your life!

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(Next week: Recent advances in the treatment of breast cancer. Don’t miss it.)