Screening for breast cancer: What every young woman should know

By Lisa Lombardi

In February 1994, while doing her monthly breast self-exam, 37-year-old Joyce Percival felt something suspicious -- a lump, she believed -- in her left breast. The Pawtucket, R.I., mother of two went to her obstetrician/gynecologist, who told her it was " ‘normal breast tissue changing,' and nothing to worry about," she recalls. But Percival -- whose mother was diagnosed with breast cancer at 37 and died of it at 44 -- remained concerned. That was her first smart move.

Percival insisted on a mammogram, which was interpreted as normal; the doctor suggested a follow-up in six weeks. By then, the lump had elongated. Even though her OB/GYN again reassured her, Percival pressed for a needle biopsy. She was told the biopsy was negative and that she should come back in eight weeks. However, she went back sooner, because the lump had grown bigger, and become tender. "My doctor said, 'Oh, don't worry, cancer isn't painful.'" Percival recalls. "But my instincts told me to ask for another needle aspiration, which he did, along with an ultrasound and mammogram. He told me the next day, 'You have breast cancer.' He wouldn't even look me in the eye."

Now comes the unbelievable part: Though Percival was diagnosed with, in her words, "a very large aggressive tumor with six involved lymph nodes," the mammogram still read normal.

"It's not a foolproof test," says Susan Braun, president and CEO of the Susan G. Komen Breast Cancer Foundation in Dallas. "But it's the best thing we have right now." Adds Lawrence Bassett, M.D., director of the Iris Cantor Center for Breast Imaging at the University of California, Los Angeles, Jonsson Comprehensive Cancer Center: "Mammograms detect cancer earlier, but they're not as good a screening test for young women, because younger women have dense breast tissue."

Of course, the question on everyone's mind these days is: Are they a good test for anyone? "There is absolutely no consensus" about the value of mammograms as a screening tool, says Donald Berry, M.D., chairman of the biostatistics department at the University of Texas M.D. Anderson Cancer Center in Houston. The debate over routine mammograms began -- at least in public -- last October, when the British medical journal The Lancet published a Danish study that analyzed statistics from several large mammography studies going as far back as 1963. Reviewing the historical data, the Danish researchers came to a shocking and controversial conclusion: Mammograms don't save lives.

A standing editorial panel (known as the Physicians' Data Query Screening and Prevention Board) within the U.S. National Cancer Institute (NCI), which is based in Bethesda, Md., then evaluated the same studies; surprisingly, it came to an only slightly more positive conclusion: The historical trials indeed had many flaws that threw the putative benefits of screening into question. However, another NCI committee (the U.S. Preventive Task Force) felt there wasn't enough evidence to discount the mammogram's role in saving lives. So NCI chose to stick with its original screening recommendations: All women 40 and over should receive mammograms every one to two years. The Atlanta-based American Cancer Society (ACS), the nation's largest private charity devoted to cancer research and education, advocates yearly mammograms for women 40 and older.

There's no doubt that mammograms are detecting more tumors, particularly more ductal carcinoma in situ (DCIS), which some experts refer to as precancers. (Mammograms are also picking up a lot of shadows: The false-positive rate is 85–90 percent, meaning if you get a suspicious mammogram, the chance it's actually cancer is only 10–15 percent, Berry says.) While breast-cancer deaths have declined about 21 percent in the past 10 years, there's debate as to whether that's due to earlier detection or the greater success of the latest class of breast-cancer drugs. In the same time frame, breast-cancer rates have risen -- especially the incidence of DCIS, an "increase" that the ACS attributes to more aggressive screening. "We're picking up more early lesions, and when breast cancer is detected earlier, women do better," says George Peters, M.D., executive director of the Southwestern Center for Breast Care at the University of Texas Southwestern Medical Center in Dallas. "Early is better and earlier still is even better."