Experts discourage frequent mammograms

Judith Graham

CHICAGO – In a highly controversial move, an influential government-sponsored organization is recommending against routine annual mammograms for healthy women in their 40s.

After re-evaluating scientific research on mammography’s ability to reduce deaths from breast cancer, the U.S. Preventive Services Task Force says these women should consult a physician and make a decision reflecting their own preferences and values. The recommendation does not apply to women at high risk for the disease.

The group had previously suggested that women ages 40 to 49 be screened for breast cancer every one or two years.

“No one is saying that women should not be screened in their 40s,” said Dr. Diana Petitti, vice chair of the task force, whose work is closely followed by doctors and insurance companies. “We’re saying there needs to be a discussion between women and their doctors.”

The new advice reflects a heightened appreciation of the potential harms associated with breast screening. No one disputes that mammograms help save lives, but they can be unreliable, identifying too many benign growths as cancerous, missing other tumors that are malignant and sometimes leading to medical interventions of questionable benefit, experts note.

The task force also is suggesting that women age 50 to 75 get the X-ray tests every two years instead of annually. There isn’t sufficient evidence to recommend screening for women 75 and older, it says.

The new recommendations, which put the group at odds with two major cancer organizations, came under immediate fire from some breast cancer specialists. Critics say the change could undermine advances in detecting breast cancer early, treating it effectively and preventing deaths, which have dropped 30 percent since 1990.

“This will be disastrous for women’s health,” said Dr. Daniel Kopans, senior radiologist in the breast imaging division at Massachusetts General Hospital.

“It’s arrogant and irresponsible,” said Dr. Robert Schmidt, a professor of radiology at the University of Chicago Medical Center. “It’s wrong to keep changing recommendations and give conflicting messages to women.”

The task force’s change of position is confusing, said Careese Anderson, 48, of Chicago, who has been getting annual mammograms at the University of Chicago for the past eight years.

“You hear one thing all these years, and it’s scary when they start saying something else,” she said.

Underscoring deep disagreements among medical experts on the issue, the American Cancer Society and the National Cancer Institute said they had no plans to back down from their current positions. The society recommends annual mammograms for women starting at age 40; the cancer institute says every one to two years for that group.

“There are differing views and to some extent differing judgments about the evidence,” said Dr. Stephen Taplin, branch chief of applied cancer screening research at the National Cancer Institute.

Dr. Len Lichtenfeld, deputy medical officer for the American Cancer Society, noted that the data reviewed by the task force shows that starting screening at age 40 and annual screening does reduce mortality.

Fundamentally, said Petitti, the difference of opinion comes down to “a judgment call … a weighing of the numbers” quantifying potential benefits and harms.

Researchers examined the issue in a new scientific analysis and a modeling study that the Annals of Internal Medicine published Monday along with the task force’s new recommendations.

The analysis looked at seven “gold standard” clinical trials along with updates from an eighth trial. It found that women in their 40s offered the opportunity to get mammograms are 15 percent less likely to die of breast cancer than those who weren’t.

That’s an important advantage, but it needs to be seen in context. At age 40, a woman’s chance of dying of breast cancer in the next 10 years is 0.19 percent, according to data from the National Cancer Institute. During her entire lifetime, that risk rises to 2.86 percent.

Meanwhile, a 40-year-old’s risk of being diagnosed with invasive breast cancer before her 50th birthday is only 1.44 percent. Most women vastly overestimate these risks and believe that starting screening younger is advisable, research shows.

The scientific analysis also found that to save one woman’s life, 1,904 women need to have mammograms starting at age 40 over the course of a decade – even though most of them aren’t at risk of getting cancer. By contrast, 1,339 women need to be screened to save one death if mammograms begin at age 50.

Meanwhile, the chance of “false positive” results (those that appear to signal cancer but turn out to be incorrect) is 60 percent higher in 40-something women than in women in their 50s, in part because younger women’s breasts are denser and harder to evaluate. And rates of over-diagnosis – the detection of lesions that would never become cancerous – can run as high as 10 percent in this group, the analysis said.

The analysis doesn’t detail how many 40-something women might die of cancer if they decided to forgo screening until they turned 50.

-The Chicago Tribune (MCT)