Detecting changes in breast cancer diagnosis
Mammograms more accurate, biopsies less painful
By Marilynn Marchione
Breast test guidelines
Here are recommendations from the American Cancer Society and federal health officials on when and how often women should be tested for breast cancer.
- Marilynn Marchione
That situation has been far from perfect - 15% to 25% of cancers are missed by mammograms, and only 20% of cases that looked suspicious on mammograms actually turned out to be cancers once they were biopsied.
Today, things are changing rapidly for the better.
Three Milwaukee hospitals already have or are in the process of installing computers aimed at boosting the accuracy of mammograms and detecting tumors that radiologists otherwise would miss.
Many area hospitals now have stereotactic needle biopsy systems, which have become a common alternative to the standard surgical biopsy that leaves women with a painful wound and a scar.
Meanwhile, research is continuing locally and nationally on promising technologies to replace or complement existing mammography and biopsy equipment.
In short, detecting and diagnosing breast cancer is cheaper, more accurate and less painful than it was a decade ago.
"When I started in radiology 11 years ago, every breast biopsy was done in the operating room," said Mark Wenzel, a radiologist at St. Luke's Medical Center. Now, nearly 90% at his hospital are done through minimally invasive techniques. "That's a huge change," and one that's better for women, he said.
October is breast cancer awareness month and Friday is national mammography day.
Breast cancer is the most common major cancer among women in the United States and the second leading cause of cancer deaths in women, after lung cancer. An estimated 175,000 cases will be diagnosed this year and it will claim 43,300 lives. In Wisconsin, an estimated 3,400 new cases will occur and 800 women will die of it.
Early detection dramatically improves survival odds, and the key tool for early detection has been mammograms - low-dose X-rays that can detect tumors years before a lump is felt.
But a key limitation has been quality.
Although mammography has been used since the 1960s, it wasn't until 1994 that detailed standards were adopted covering all health care professionals involved in it, from the physicists who compute radiation doses and calibrate machines to the technologists that position women's breasts. Mammography facilities and equipment now are required to be certified by the Food and Drug Administration.
Beyond the equipment-related issues are the limitations of human accuracy and skill. False negatives and false positives are common with mammograms. Studies show that 15% to 25% of breast cancers are missed, and many of the misses are radiologist-related.
Reducing those percentages is the goal of the first computer-assisted mammography system approved by the FDA - the R2 Image Checker. Columbia Hospital became the first Wisconsin hospital to install the system about a year ago, and it recently was added to St. Mary's Hospital in Milwaukee as part of an expanded breast-imaging center. Plans are to do the same at St. Mary's Ozaukee in February, and several other area hospitals are considering purchasing the system, too.
"I've been following this technology for years," said St. Mary's radiologist Henry Bradley. "This is the mammographic equivalent of a spell checker."
After a radiologist has looked at the X-ray, the computer analyzes the digital image and highlights areas of possible abnormalities - differences in density, calcifications, asymmetry - that the radiologist may have missed. Those areas are flagged to the radiologist, who can enlarge, increase the contrast or otherwise manipulate the image to get a clearer view of a possible problem area.
Wenzel said St. Luke's, St. Luke's South Shore and Sinai Samaritan Medical Centers have not bought Image Checker because all mammograms are double read - analyzed by two radiologists - at each hospital.
Once mammograms have identified a possible problem, an array of follow-up tests are available to diagnose whether cancer is present:
Ultrasound uses sound waves to help determine whether a lump is solid or filled with fluid. Fluid-filled masses often are benign cysts.
Fine needle aspiration can be done as well. Using ultrasound as a guide, a needle is inserted in the lump, and fluid and cells are removed. If it's a cyst, it should collapse. If it is solid, it could be benign or malignant, and further diagnostic work may be needed. More tests also may be needed if the fluid has blood in it, is thick or is of an unusual color.
Then there's biopsy to obtain a tissue sample, and a variety of ways to perform it. For a traditional surgical biopsy, a mammogram is used to place a wire in the breast to locate the suspicious lesion so a surgeon knows what to remove and send to pathology for analysis.
But far more common these days is the stereotactic needle or core biopsy, which first appeared in the Milwaukee area in 1994 at St. Mary's, St. Luke's and a private diagnostic clinic operated by radiologist John Milbrath in Waukesha County.
The procedure requires only local anesthesia and leaves no surgical scar. A woman lies on her abdomen on a special table, with her breast protruding through an opening, or sits in a chair with her breast through an opening of an imaging device. An X-ray tube is positioned to produce two (stereo) images of the abnormality. Based on those images, a computer guides a wide-bore needle to rapid-fire into the breast site and remove a sliver of tissue that is sent to pathology for analysis.
Multiple cores often are taken because tumors may have both benign and malignant areas. And that's the major advantage of an upgrade to the stereotactic system called the Mammotome, which automatically takes multiple samples from a single insertion.
"The needle is only placed in the breast one time, which is a big advantage," Wenzel said.
The Mammotome is available at Waukesha Memorial, St. Luke's, Sinai Samaritan, St. Francis, Elmbrook Memorial, St. Joseph's, Columbia, St. Mary's Milwaukee and will be added at St. Mary's Ozaukee in February. Other stereotactic systems are available at St. Michael, West Allis Memorial, St. Luke's South Shore and Community Memorial in Menomonee Falls.
On the research front, there are these local developments:
University of Wisconsin-Madison researchers William Wolberg and Olvi Mangasarian are working on perfecting a computer model they developed more than five years ago to diagnose samples of breast cells as cancerous or benign.
First they "taught" the computer the difference between benign and malignant cells by feeding it digitized images and data on two sets of samples - some known to be benign and others known to be malignant. The computer now can distinguish between benign and malignant on new breast tissue samples with 97% accuracy, Wolberg said.
But the main potential use for the computer program is that it will become a common and reliable tool for predicting prognosis. By analyzing the nucleus of the breast cells for certain features, the computer has outperformed methods used now - measuring tumor size and checking for cancer in nearby lymph nodes - for predicting whether a patient's cancer will recur.
Wolberg's hope is that the computer will eliminate the need to remove lymph nodes after a mastectomy or lumpectomy is performed to decide whether a patient needs chemotherapy as a follow-up treatment.
Since Wolberg described the work at a cancer society scientific meeting in 1994, he has added more breast cell samples to boost the program's "experience" level, and has adapted the program so it doesn't require a special work station and can be operated on an ordinary PC computer.
UW researchers Susan Hagness and Frederick Kelcz are trying to adapt radar technology that's used to detect land mines into a new tool for detecting breast cancer.
Hagness recently got a grant from a private engineering research foundation to continue her work with microwave radar imaging, which uses low powers of the same kind of microwaves used in digital cellular phones. Tumors have a higher water content than normal tissue, and 3-D images of a tumor can be produced by the scatter pattern from the microwaves.
The big advantages of microwave technology is that it is inexpensive and does not involve or use radioactivity.
So far, the research has been only on breast biopsy samples, not women enrolled in clinical trials. Work is focusing on determining whether the technology can detect extremely small tumors and whether it can distinguish between malignant and benign tumors, Hagness said.
For information on facilities in your area that offer mammograms, call the American Cancer Society, (800) 227-2345; the National Cancer Institute, (800) 422-6237; the National Alliance of Breast Cancer Organizations, (888) 806-2226; or Y-ME, (800) 221-2141.