Screening for breast cancer: What every young woman should know
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."
DCIS: A 50/50 risk
However, some experts like Berry aren't so sure. "One of the risks of screening is finding disease," he says. "It sounds silly, because that's what we're trying to do, but with mammograms, you find a lot more disease -- some should be treated, and some should not." The fact is, if left untreated, half of women with DCIS will go on to develop invasive breast cancer, but half won't.
"This is the issue in breast cancer right now," says Madeline Crivello, M.D., a breast-cancer survivor and director of women's imaging at Mount Auburn Hospital (an affiliate of Harvard Medical School) in Cambridge, Mass. "How do we differentiate the bad kind of DCIS from the harmless kind that doesn't need to be treated?"
Researchers are now working on developing a marker to distinguish the two breeds of DCIS. In the meantime, though, a woman facing a DCIS diagnosis is in a real bind, Crivello says. "How aggressively does she treat DCIS? Does she say, 'I don't think this will be a problem,' then in five years find out she has an invasive tumor? Or does she have a mastectomy that she may not need?"
Mammograms under 40
If you're wondering where the debate leaves women under 40, the answer is: Exactly where they were before last October -- without an ideal screening test for breast cancer, says Diane Balma, director of public policy for the Komen Foundation and an early-breast-cancer survivor. According to the NCI, ACS, Komen Foundation and most other breast-cancer experts, women under 40 do not benefit from mammography. And, unless they have significant risk factors such as a strong family history of the disease (a first-degree relative -- mom, sister, or daughter -- diagnosed with premenopausal breast or ovarian cancer), they should not receive it.
And as for that baseline mammogram for women at age 35? "There's a lot of confusion about that, but the American College of Radiology stopped recommending it four or five years ago," Crivello says.
The medical community has moved away from the baseline for three main reasons: First, young women's breasts are so dense that mammograms often fail to detect cancer anyway (as Percival experienced).
Second, breast cancer is relatively uncommon in young women. At 30, your chance of being diagnosed (assuming you don't have special risk factors) is one in 2,000; at 35, it's one in 600; and at 40, it's one in 225. (As for that one in nine stat? That's the average risk if you live into your 80s.)
And third, "We can't expose all 35-year-old women to radiation if it might only help a very small percentage," Peters says.
Most experts say that while the amount of radiation is relatively minor, it's an issue because young women's breasts are more sensitive to radiation than older women's are. "It's a concern," Berry says. "It may not be a very large amount of radiation, but unfortunately we don't really know whether it could cause cancer or help breast cancers along." Ironically, he says, women with strong family history and women who have tested positive for one of the genetic mutations linked to breast cancer -- BRCA-1 and BRCA-2 -- are encouraged to get earlier and more frequent mammograms than the general public. "But there's some lab evidence that people with these genes are especially susceptible to radiation, so having these women get mammograms may in fact be encouraging more breast cancer," he says. "It's pure speculation at this point, though."
One expert who doesn't believe it's speculation is Samuel Epstein, M.D., professor emeritus of environmental medicine at the University of Illinois at Chicago School of Public Health and chairman of the Cancer Prevention Coalition. "Women need to know that the radiation you get from screening mammograms, particularly premenopausal women, increases your risk of breast cancer," he says.
One film requires around 250–300 millirads of radiation (the U.S. Food and Drug Administration requires that each X-ray produce no more than 300 millirads). If standard practice is four films, Epstein contends, women are receiving more than one rad -- 1,000 times that of one chest X-ray focused on the entire chest.
But your cancer risk from that is very small, counters David Brenner, Ph.D., professor of radiation oncology and public health at Columbia University in New York City. "The radiation dose from a mammogram is about equivalent to our annual exposure to naturally occurring radiation. The risk of this low a dose of radiation causing a fatal cancer isn't quite zero, but it's roughly one in 1 million for a single examination and one in
100,000 for 10 annual mammograms. So the radiation risk is very small compared to the benefits of early detection for an older woman who has a much higher chance of developing breast cancer. And your radiation-exposure risk goes down quite a lot as your age goes up. The later you start, from a radiation perspective, the better."
As the debate rages, the practical question of whether to get screened falls more and more on individual women and their physicians. What about those of us younger than 40 without significant risk factors? The options are clinical breast exam, which the ACS recommends every three years from 20-39 and yearly after 40, and breast self-exams, which the ACS recommends women perform monthly.
While even breast self-exam is controversial ("No study has ever found it prevents cancer deaths," Berry says), the fact is most younger women with breast cancer find it on their own, says Maureen Chung, M.D., Ph.D., surgical oncologist at the Breast Health Center at Women and Infants Hospital of Rhode Island in Providence. Young women who find something suspicious should receive not only a mammogram but an ultrasound, which is a far more sensitive test than a mammogram and better able to pick up suspicious masses in dense tissue.
If you have some anxiety about doing breast self-exams, don't worry. "Women shouldn't be made to feel guilty if they aren't comfortable doing them," Crivello says, a sentiment that's echoed by Berry and Peters. Just keep in mind that if you aren't doing them, it's even more critical to get a clinical breast exam done by your doctor or nurse once a year. While the official recommendation in the 20–39 group is once every three years, "if your OB/GYN isn't doing it every year when you go in for a Pap smear, that's malpractice," Crivello says. And if you're really concerned, there's no reason you can't go in to your doctor or nurse two or three times a year, Bassett adds.
The bottom line, say experts, is young women shouldn't live in fear of breast cancer. Instead, you should control what you can control. That means you should lead a healthy lifestyle (see sidebar below), show up for yearly exams, and be sure to ask your primary-care doctor for a referral to a high-risk clinic if you have a mother or sister who was diagnosed with premenopausal breast cancer. As for mammograms, the majority of experts agree that if you're under 40 without significant risk factors, you don't need one. But there's still debate about whether women in their 40s -- particularly their early 40s -- benefit from screening. That means for the time being, it's up to you to decide whether to follow NCI's guidelines (every year to two years starting at age 40) or to discuss this issue further with your OB/GYN or other respected medical professional.
Above all, say breast-cancer doctors, researchers and survivors, trust your gut. "Know your own body and don't be afraid to speak up," Peters says. "I see every day how it helps: the persistence of patients coming in and saying, 'This doesn't feel right.' The mammogram will be negative, but we'll go ahead and do the needle biopsy and catch it really early."
Percival, who had a mastectomy and reconstruction of her left breast and is now cancer-free, adds this: "I really believe if I hadn't had this gut feeling and gone with it, and kept going back to the doctor and insisting on follow-up, I might not be here today."