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HEATH HORIZONS : MEDICINE : Mammography--Vital but Not Foolproof : IT IS THE ONLY TECHNOLOGY CAPABLE OF FINDING BREAST CANCER IN ITS EARLY STAGES, WHEN THE CURE RATE IS 91%. BUT THERE ARE INHERENT LIMITS, ESPECIALLY FOR WOMEN UNDER 50.

March 29, 1992|KATHLEEN KELLEHER | Kelleher is a free - lance writer in Los Angeles. and

Mary Stupp had her first mammogram in 1987 when she was 57. It read: "normal." A few months later she felt a small lump in her breast, but waited to have it checked during her next annual mammogram. Once more she was reassured. It read: "no malignancy."

But when her breast skin dimpled, the professor of philosophy at Mountain View College in Dallas decided to see her internist instead of going back to the mobile facility that had taken her previous mammograms. Her internist read reports from the two exams but did not view the mammograms himself. He gave her a clinical exam during which, Stupp says, he felt the lump. He assured her that there was nothing to worry about.

When Stupp went back to her physician for her annual mammogram a few months later, a suspicious-looking lump appeared on the film. Two days later, Stupp's breast was removed. The tumor was the size of a lemon.

When Stupp finally managed to get her original mammograms from the mobile facility (operators first said the X-rays were lost, she said, and later sent them), the two X-rays showed clear evidence of suspicious-looking abnormalities. Now ill with inoperable cancer that has spread throughout her body, Stupp is dying. Her family sued the radiologists who read her first two mammograms.

Ruth Green (a pseudonym) of Sacramento had a more positive experience. Green was 47 when she went to her family doctor for a general check up and a mammogram. Something suspicious appeared in her X-ray, and a second mammogram was taken that clearly revealed a cancerous looking lump in her left breast.

After a biopsy confirmed that the lump was malignant, Green's breast was removed along with a tumor the size of a golf ball. Doctors believe they caught the cancer early enough and expect her to live a normal life span.

The polar experiences of these two women demonstrate some of the problems and drawbacks of the science and application of mammography. Mammography is the only technology capable of finding breast cancer in its early stages--two years before a woman can feel it with her hand and before it has spread beyond the breast into the lymph nodes. At this stage, a cancerous growth is about the size of a garbanzo bean and has been growing about five years.

The advantage and importance of early mammographic detection cannot be exaggerated. There is a 91% cure rate when cancer is found at this point. Cure rate in this context means that doctors expect a woman to die of causes other than breast cancer.

But mammography, an X-ray of breast tissue that shows potentially cancerous shadows, is fallible and has inherent limits. About 10% of breast cancers cannot be detected in mammograms. In women under 50, whose breast tissue is dense and lacks fat, mammograms fail to spot about half of breast cancers, according to the December issue of Consumer Reports on Health. In women age 50 and older whose breast tissue is very fatty and where mammograms are most successful, mammograms may still miss one-tenth of cancers.

Then there are tragic incidents unrepresented by numbers, like that of Stupp, where a mammogram that shows some abnormality in breast tissue is not followed up with a biopsy or further tests.

Mammograms alone are not reliable and accurate enough to diagnose cancer. Even when mammograms detect an abnormality, 90% of abnormalities that cannot be cleared as benign findings from the X-ray turn out to be benign after a biopsy is performed.

In the general screening population (women going for regular screenings) false-positive readings (abnormalities followed by biopsies that are benign), range between 60% and 70%, says Dr. Lawrence Bassett, director of UCLA's Iris Cantor Center for Breast Imaging. Bassett says false-negative readings occur about 10% of the time.

Despite this margin of error, mammograms are the most technologically advanced method used for screening breast cancer. Magnetic resonance imaging, an expensive and lengthy screening process used for brain, spine and muscular skeletal X-rays, is still being explored as a detection device for breast cancer at the UCLA center and at Baylor University in Texas. MRI uses magnetic fields and radio waves to get an image of the body.

This year, breast cancer will take the lives of 44,500 women and occur in 175,000 more women. It is the second-leading cause of death of American women after lung cancer. It will invade one in nine women during their lifetime--up from one in 11 in 1980. Experts say the value of early detection is that it could save the lives of 30% of women who might otherwise die of the disease.

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