Physicians can find themselves in the middle of medical guideline debates

The U.S. Preventive Services Screening Task Force, specialty societies and disease advocacy groups promulgate guidelines for prevention of illness and disease. Sometimes screening recommendations from different groups -- for the same condition -- are not in sync.

Reply: Consider two patient questions. The first patient is a 46-year-old woman coming to see you for a routine visit. Last year she had a mammogram. She has no family history of breast cancer. Based upon the U.S. Preventive Services Screening Task Force, you recommend waiting until she turns 50 before starting yearly mammograms. She asks you to explain why she should not get a mammogram now, as the American Cancer Society encourages. Having read about the mammography controversy in the newspaper, she says she is confused and needs your interpretation.

The second patient is a 62-year-old man coming in for a routine yearly visit. He asks if he should get a prostate-specific antigen test. He has read that guidelines for PSA testing by various disease advocacy and specialty groups differ from the task force's guidelines and wants you to explain the controversy and give your opinion.

We face these situations regularly, both with patients and friends. When experts disagree, the debates are interesting, but, as practicing physicians, we can find ourselves in the middle.

Guidelines represent an attempt to review all the available and relevant data and recommend a course of action for a clinical situation. Why, then, should they differ? One important reason is that human beings create them. Guideline panels review the data, but data always require interpretation. When experts interpret data to create guidelines, they make subjective judgments. The "affect heuristic" influences these judgments and thus the guidelines that depend on those judgments. Daniel Kahneman writes about this heuristic in his new book, Thinking, Fast and Slow.

The affect heuristic acknowledges that people's likes and dislikes influence their interpretations of risk and benefit. Thus, oncologists heavily weigh the benefits of finding breast cancer, while minimizing the burden of side effects that patients may experience during screening. Likewise, urologists weigh the benefits of finding prostate cancer more heavily than they do the complications of treatment or procedures that follow from false positive screening tests.

We can attribute resulting guidelines to the influences of affect heuristics on guideline panels, without accusing them of any conflict of interest. We need not criticize the oncologists or the urologists for their opinions; we must understand that the decision heuristic influences how they weigh the evidence. Since humans construct guidelines, guidelines always will have subjectivity.

The task force is an independent panel of nonfederal experts in prevention and evidence-based medicine and is composed of primary care health professionals (such as internists, pediatricians, family physicians, gynecologists/obstetricians, nurses and health behavior specialists). These experts review the data from the viewpoint of the patient.

This explains, in part, why controversies occur, and it makes the physician's role in explaining guidelines to patients difficult and critical. There are other reasons, of course, why guidelines change. Medicine is not a static science. As new clinical research studies become available, each panel evaluates those data and reconsiders its recommendations. The past 30 years have seen major changes in our knowledge of disease treatment. Any guideline represents an attempt to interpret and integrate the current data. In the case of prostate cancer, for example, prospective studies have better defined the risks and benefits of screening. These new studies provide objective data, but interpretation of the data always will remain subjective.

Explaining risks of screening

Most people do not understand the factors that go into screening guidelines, and they don't understand the risks of screening; they only imagine the benefit of finding cancer early. Our aim, when we meet with patients, should be to educate them fully enough about the risks and benefits of screening so they can make a decision that accords with their health goals and considers their fears.

The Foundation for Informed Medical Decision Making provides information and even patient-specific aids for several difficult decisions, including the two that we are discussing here. The general principle that we must convey is that all screening has pluses and minuses. Before we can recommend screening without qualifications, we must be convinced that finding a disease early increases the cure rate without causing too many complications.

Changing or competing guidelines put physicians into a complex ethical position. We run the risk of criticism regardless of our recommendation. If we do not advocate screening and the patient is diagnosed with cancer soon thereafter, we are susceptible to severe criticism. If we advocate screening and the patient undergoes uncomfortable and unnecessary follow-up that reveals no cancer, we are susceptible, likewise, to severe criticism.

The truth is that these clinical situations do not have clear solutions.

We really need a "meta" breast cancer screening guideline that looks at the differences in existing guidelines and explains that, before age 50, the decision about whether the woman should have a mammogram depends on many factors. The decision is individual, based on the patient's family and medical histories, perceived risk of cancer and tolerance for further evaluation (biopsies and other imaging tests).

Likewise, we need a prostate cancer screening that admits we are not certain that the prostate cancers we find with PSA screening need immediate treatment. We should make explicit the dangers of screening -- biopsies and their complications -- and of treatments that have significant side effects, and we should admit the impossibility of knowing whether a given cancer will need treatment during the patient's lifetime.

Our job with patients who come in having heard new or conflicting guidelines is to explain, as clearly as we can, that the guidelines do, indeed, change over time. Patients also should know that no matter how longstanding or widely endorsed a specific guideline is, it cannot tell him or her what he or she should do. That's where individual family history and the patient's medical history, comorbid conditions and age come in. Sometimes these factors place the patient squarely in the middle of a group for whom screening is recommended, and sometimes not. Point out to your patient that what a friend's or relative's doctor advised might not be the right advice for your patient.

This type of individual education and counseling takes time, but at the end of the discussion, the patient should be able to explain what his or her individual screening risks are, or what benefits she or he might gain from screening. Then, considering these in light of personal health goals, fears and tolerance for possible follow-up testing, the patient can decide whether to be screened. We should use guidelines in this way, remembering always that they are guidelines, not rules.

Robert M. Centor, MD, professor and chief, Division of General Internal Medicine, University of Alabama at Birmingham; associate dean for the Huntsville Regional Medical Campus