But not everyone is convinced.
For decades, doctors and advocacy groups have urged women to examine their breasts every month for unusual lumps.
Now many of those same experts have a different message: Never mind.
Earlier this month, Danish researchers published the latest report to cast doubt on the value of monthly exams. In studies of nearly 400,000 women, they found that even diligent self-examinations don't save lives. In fact, they may do more harm than good, by triggering a lot of unnecessary followup tests.
Over the last few years, cancer experts have quietly backed away from what was once considered a pivotal part of the fight against breast cancer.
"I don't think that we're pushing it as much as say, 10 years ago, when you used to ask every patient 'are you doing it?'" said Dr. Andrea Flom, head of the Minnesota chapter of the American College of Obstetricians and Gynecologists.
It's an open secret that many women don't do self exams correctly -- or at all.
That was evident in interviews with more than half a dozen women in downtown Minneapolis last week. None said they did the exams regularly, though all but one thought they were still recommended.
"It's like flossing your teeth: you know you should do it, but ..." said Sheryl O'Connor, 53, of Minneapolis. Now, she said, it's a relief to know that exams are fading in importance. "Perfect, one less thing for me to feel guilty about."
Diana Wengler, who was visiting from Houston with two teenage daughters, said she had no idea that the advice had changed. "It surprises me," she said, adding that she's heard the mantra about the importance of monthly exams "forever."
In fact, the American Cancer Society stopped recommending breast self-exams five years ago and now calls them "optional." Some clinics have stopped circulating brochures on how to do them. Even the Susan G. Komen organization, best known for its Race for the Cure, decided last year to drop the recommendation.
Slow to change
"It has been a bit of a culture change within the organization," admits Dr. Eric Winer, Komen's chief scientific adviser, who is also director of breast oncology at the Dana Farber Cancer Institute in Boston. In spite of the policy change, Komen has yet to remove the advice from its website, which still recommends monthly self-exams. "Let's just say the Web site is evolving," Winer said.
For years, it was believed that self-exams could find breast cancer in its earliest stages, when it's most treatable.
But doubts have been growing since 2002, when a huge study in China found that women who checked their breasts monthly were no less likely to die of breast cancer than other women, in spite of intense coaching in how to do the exams properly.
This month, scientists took a fresh look at the growing body of evidence, including a huge group in Russia. Once again, they found no sign that self exams cut the death rate. Instead, the women who examined their own breasts found more harmless lumps and had twice as many unnecessary biopsies as other women, according to a July 15 report published by the Cochrane Library. The conclusion: Self-exams "cannot be recommended."
'Absurd and outrageous'
Some are appalled. "It is simply absurd and outrageous to suggest women should not examine their breasts because it will do more harm than good," wrote Dr. Marie Savard, author of "How to Save Your Own Life," on the ABC News website last week. "After reading this report, some may conclude it is better that women remain in the dark about their bodies and rely only on technology. ... Ridiculous."
But more and more, doctors are walking a fine line.
"In general, what we say at Piper is that we recommend it as just one more way to find an early breast cancer, but it has shown to be the least important way," said Dr. Beverly Trombley, a radiologist who specializes in breast imaging at Abbott Northwestern Hospital's Piper Breast Center. Mammograms, she said, are "by far the most important."
One reason for the change of heart is technological.
"You used to find breast cancer by feel, and the technology changed," said Trombley. "We're finding fewer of them by feel and much more of them by imaging."
Along with mammograms, experts now emphasize what they call "breast health awareness." Essentially, that means being aware of changes in the breast, without necessarily going on a monthly scavenger hunt. If a woman finds something amiss, say, during a routine shower, he said, she should notify her doctor and check it. He notes that many women have found lumps that way, rather than through formal self-exams.
Flom, a Twin Cities obstetrician, admits that doctors may be sending mixed messages. "You sort of get this ambivalence," she said. "I'm not going to tell a patient who does [self exams] every month 'you need to stop doing that'. I'm not. But if I have somebody who never checks their breasts, I'm not going to tell them 'you need to start tomorrow.'"
Maura Lerner • 612-673-7384