New Cancer screening guidelines raise concern

by Carol Crump
Tuesday, November 24, 2009 12:36 PM MST

The mantra for breast cancer prevention has been early detection, including self-examination and routine mammograms starting at age 40. The protocols are heartily endorsed by the American Cancer Society, and approximately 39 million women undergo mammograms each year in the United States.

Most of the approximately 182,460 American women diagnosed with breast cancer each year are diagnosed as a result of screening. The advocacy group estimates that breast cancer mortality in the U.S. has dropped about 10 percent because of screening.

In spite of breast cancer’s status as the leading cause of death for women between the ages of 40 and 49, the U.S. Preventive Services Task Force recently recommended that women in their 40s stop routinely having mammograms. Older women, from 50 to 74, were told to cut back their screenings to every other year, even though age is one of the strongest risk factors for breast cancer. The federal task force also recommended against teaching women doing self-exams or having doctors doing them.

“This is just not the right direction,” Rocky Mountain Oncology Dr. John Purviance said of the recommendations. “We’re getting better; the death rate has declined, in large part due to mammography screening. To slacken effort at this point just doesn’t make sense.”

The recommendations were based on a comprehensive analysis of medical literature that included an update on a Swedish study of about 70,000 women, a British trial involving 160,000 women, data from the Breast Cancer Consortium on about 600,000 women, and six independent teams of researchers funded by the National Cancer Institute.

One of the problems with the risk-benefit analysis that concluded that the harms of mammography outweigh its benefits could be the data’s dependence on film mammography rather than digital mammography results, according to Purviance.

Detecting breast cancer early

Digital mammography, which is widely available and in use in the U.S., is already doing a better job of detecting cancer in the 40 to 50 age group and computer recognition technology advances are better able to discern cancer.

“If we pull the plug, we lose the opportunity to save women in their 40s. The tool is already improving,” he said.

Purviance questioned the task force’s “unfortunate” argument that it’s unfair to subject women to the stress, radiation and possibly unnecessary biopsies or disfiguring surgery that can be caused as a result of false-positive routine mammograms. Mammograms produce false-positive results in about 10 percent of cases, so the anxiety is out there, Purviance said, but there are ways that the medical community could better address it. Patients could be better informed that a repeat mammogram or a biopsy doesn’t automatically indicate terminal illness

“Look at it as a process rather than a death sentence,” he said.

The process is admittedly slow, but Purviance pointed out that Wyoming women are fortunate that the turnaround time for results can be the next day.

“They’re using that to discourage mammograms,” he said. “When you look at the data, there’s a survival advantage.”

Mammography detects about 75 percent of breast cancers in women in their 40s and about 90 percent of breast cancers in women in their 50s and 60s, according to the National Institute of Health. Women in their 40s do have a lower incidence of breast cancer but breast cancers in younger women are more aggressive and faster growing. In that age group, breast cancer is the second highest cause of death behind accidents.

“It’s the difference between seeing kids graduate from high school and marry,” Purviance said, recalling a woman with Stage IV breast cancer who was pregnant. “She was dead before her child could remember her.”

The local radiation oncology also is seeing women in their 50s with breast cancer who are raising grandchildren. “It affects families in profound ways,” he said, adding that cost effectiveness doesn’t take the impacts into account.

Statistics based on risk-benefit analysis

Mammography is one of the most common medical tests, and the annual cost to the health care system is more than $5 million. Purviance said the task force’s conclusions are based on a statistical risk-benefit analysis of cost effectiveness. Mammograms do reduce the risk of death for women between the ages of 40 and 49 by about 15 percent, but that percentage may not be enough to justify the procedure’s costs in a group that accounts for about one out of six breast cancers.

Purviance explained that mammograms of 2,000 women would generate a certain number of biopsies and only a smaller number, something like 500, would have cancer. The cancer rate steadily climbs as women age.

“What they’re really saying is it’s not worthwhile to spend money that could be spent elsewhere to help get more years of life,” he said.

A 1997 recommendation from a federal committee of medical experts against routine mammograms for women in their 40s prompted a unanimous U.S. Senate vote challenging the findings. Twelve years later, a different panel, the U.S. Preventive Services Task Force, again made the same recommendation and added distrust of self-examination into the mix.

A U.S. House health subcommittee will be holding hearings next month on the latest recommendations.

In the meantime, the American Cancer Society continues to recommend annual screening using mammography and clinical breast examinations for women beginning at age 40.

“The test is far from perfect, but it’s the best way we have to find tumors early,” said American Cancer Society chief medical officer Otis W. Brawley in an opinion piece. “How many lives are enough to make routine screening worth it?”

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