Statistics of breast cancer leap from billboards and public service ads everywhere: One out of nine women will develop the deadly disease if she lives to be 85.
Thirty years ago, it was one woman out of 16.
Although these numbers are partially influenced by earlier cancer detection and longer life spans, no one knows why the incidence of breast cancer is growing. And breast cancer activists point out that mortality rates remain virtually the same as they were in the 1950s.
It also appears the disease is increasing in younger women. Roughly 30,000 women in their 40s will develop breast cancer this year, even though it is considered primarily a disease of aging. A leading cause of death for women in this age group, breast cancer tends to act more aggressively in younger women, doctors say.
Lacking knowledge of how to prevent the disease, a woman's only defense is to find it soon enough to improve her odds of surviving it. The best early detection device is mammography, an X-ray technology which can find some cancers two years before they can be felt.
Many physicians recommend that women in their 40s have annual screening mammograms because of their susceptibility to fast growing cancers.
But some question the effectiveness of screening mammograms for younger women. Although studies have shown them to reduce cancer mortality by 30 percent in women over the age of 50, recent reports have increased doubts about the effectiveness of screening mammograms alone at detecting cancer for women in their 40s. Radiologists say the denser breast tissue common to younger women often obscures lumps which aredetected in the mammograms of older women whose breasts contain more fat.
"Mammography misses 9 to 15 percent [of cancers] and it generally misses more in women who tend to be younger," says radiologist Cynthia Swann, who specializes in breast imaging at Schulz, Snyder and Associates.
Others in the health establishment also emphasize that mammograms are fallible. Dr. Joe Aisner, director of the University of Maryland Cancer Center, compares the difference in reading the X-rays of younger women and those of older women to looking for something through a glass which is very smoky rather than clean.
Physicians say a mammogram is merely one part of regular screening which should also include a physical breast examination to detect lumps undiscovered by the mammogram. Women should also examine their breasts every month.
Earlier this year, advance reports from an unpublished Canadian study suggested that screening mammograms provided no benefit in cancer detection in women under the age of 50. The reports were quickly denounced by American radiologists familiar with the study who claimed that much of the equipment used in the study was of poor quality and that many of the technicians were insufficiently trained.
Also controversial are American studies, conducted in the 1960s and '70s, of the effectiveness of screening mammograms for women in their 40s. Some cancer experts like Dr. Aisner believe those findings show a clear benefit for younger women.
Others, like Dr. Barry Kramer of the National Cancer Institute, say the results are inconclusive. Associate director of NCI's early detection and community oncology program, Dr. Kramer says he will reserve judgment on the Canadian study, the first to focus exclusively on women under 50, until it is published next month.
Screening mammograms are given to women without any symptoms of breast abnormalities or a history suggesting them. Consultative mammograms are more extensive X-rays for women who report specific problems or have a history at risk for the disease.
Since 1987, the NCI, the American Cancer Society and most physicians have recommended women get screening mammograms every one to two years after the age of 40 and every year after the age of 50. These guidelines are used by many health insurance providers; mammograms can run as high as $120.
"Right now there is absolutely no test for breast cancer that is as sensitive as the combination of a mammogram and a physical examination," says Dr. Kramer. "Nothing has been tested and tried and met the same degree of rigor. Everyone is looking for a better diagnostic test, but at this point, nothing measures up to the mammogram."
Some possible successors and additions to mammography technology are under development. They include an optical mammography technique using ultrashort pulses of laser light; PET scans, a computer-aided imaging technique; new ultrasound procedures and magnetic resonance imaging. There is also talk of developing a blood test to detect breast cancer.
"Mammography is kind of like the United Nations: It's not perfect, but it's all we have," says Nancy Evans, vice president of the national Breast Cancer Action group.