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Vol. LXV, No. 19
September 13, 2013

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WhenScience, Policy, Politics Mix
Petitti Reviews Screening Mammography Guidelines

On the front page...

Dr. Diana Petitti borrowed a movie title from Clint Eastwood for her recent NIH talk.

Dr. Diana Petitti borrowed a movie title from Clint Eastwood for her recent NIH talk.

When a government-supported task force changed its screening mammography guidelines in 2009, Dr. Diana Petitti found herself at the center of a public uproar.

As an epidemiologic expert on women’s health and evidence-based medicine and disease as well as a specialist in biomedical informatics, Petitti was vice chair and spokesperson for the U.S. Preventive Service Task Force’s embattled new recommendations.

She recently visited NIH to talk about her experience in “Screening Mammography: Science, Policy and Politics—The Good, the Bad and the Ugly,” NCI’s annual Advances in Cancer Prevention Lecture in Masur Auditorium.


“This is the really controversial part of the recommendations,” she said, “that the decision to start screening before the age of 50 should be an individualized decision, taking into account preferences and the context.”

Reversing its previous guidelines released in 2002, the task force said that, based on current research:

  • Women in their 40s should not routinely get mammograms unless they have a high genetic risk.
  • Instead, women 40 to 49 should consult their physician about when to start screening.
  • Women 50 to 74 should get a mammogram every 2 years.
  • The panel made no recommendations for women 75 and over.

Petitti stressed that the recommendation against routine screening to begin automatically at age 40 was widely misinterpreted. The task force gave routine mammograms for women ages 40 to 49 a C rating, which meant they would not automatically be covered by insurance, including Medicare. But the panel did not say that women in this cohort should never be screened.

Their findings drew on more than 2,500 studies and 9 randomized clinical trials involving more than 600,000 women. Petitti defended the guidelines as “good science…In making science-based recommendations about age and interval,” she continued, “in fact there are no trials that randomize women to one-or-another screening interval or to one-or-another age to start screening. In fact, such trials would be extremely difficult to do and they haven’t been done.”

Mammography, a test to detect breast cancer, decreases mortality across all age groups. Around 35 million women get mammograms annually at a total cost of $5 billion. But the procedure is not without harms.

“The decision about what should or shouldn’t be recommended,” Petitti said, “is inherently a
tradeoff of those benefits and harms and involves judgment.”

Harms include radiation exposure, pain, adverse responses to false positive mammograms, overdiagnosis, the need for additional imaging and biopsies when women have had a positive screening mammogram.

Petitti cautioned, “It’s almost impossible to communicate in a politicized environment.”

Petitti cautioned, “It’s almost impossible to communicate in a politicized environment.”

Photos: Bill Branson

“We may not have agreement about how to weigh the consequences of those tradeoffs,” she said. “Now this gets translated into policy, and policy is a course of action; and in medicine and health, policy often refers to what insurance companies or Medicare or Medicaid will cover.”

The task force findings, published in November 2009, ran into the fierce headwind of congressional debate over the Affordable Care Act.

“I have to tell you that I was utterly unprepared to be the spokesperson for a topic this controversial,” Petitti said. “I really knew the data, I really knew the models, I went through all sorts of press training...”

But complex, highly numeric issues are difficult to communicate. Petitti wasn’t ready for the news van driving up to her house while she was still in her pajamas. Someone even tried to have her fired from her job at Arizona State University. It was like being thrown into the fire, she said.

“One of the most important facts that was lost in the discussion,” she stressed, “is the degree to which different modelers’ strategies and assumptions came up with the same overall conclusion about the tradeoffs of risks and benefits comparing an earlier—versus the later—starting age and a frequent—versus less frequent—screening interval.”

Meanwhile the ACA, which became law in March 2010, contained a specific repudiation of the task force’s new guidelines:

“…the current recommendations of the United States Preventive Service Task Force regarding breast cancer screening, mammography and prevention shall be considered the most current other than those issued in or around November 2009,” according to the statute.

Result: For women over 40, routine screenings every 1 to 2 years must be included in coverage plans without a copayment or co-insurance. The section of the law that deals with Medicare contains similar wording.

“We have really good science,” Petitti insisted. “I think we have really bad policy…I don’t think that a linkage of a specific recommendation of a specific group [like the task force]—where the group can change, its procedures can change—to automatic coverage for all kinds of insurance is good policy.”

Moreover, in her view, policies based on data, unless it’s the “most current data,” are unwise. Data can change relatively fast; legislation is not as nimble.

“My own conclusions and observations are that there’s a lot of good science about mammography, and that good science has the potential to inform good policy,” she said. Yet “it’s almost impossible to communicate in a politicized environment.”

During the discussion, a breast surgeon from Vietnam observed that breast cancers there are being found in “a much younger age group.”

“I think the decision about when to be screened,” Petitti replied, “has to take into account the background incidence of breast cancer. One of the questions that has come up in other forums is whether or not African-American women should be screened earlier…Are they a special group? And it may be that in your country, there are special epidemiological circumstances that would warrant a different recommendation.”

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