Weigh preventive screenings' cost-benefit ratio

The public is constantly being urged to undergo screening. Ads in buses and subways hype oral cancer screening; radio and TV commercials tout full-body CT screens. What is a physician's best course of action?

Reply:

Every day, physicians see a significant proportion of patients for screening-related visits. Common reasons for the visits include discussing recommended screening tests, answering questions for patients at risk, and evaluating patients who have had a screening test with abnormal results.

The number of cases seen is due, in part, to the recommendations for screening publicized by many advocacy organizations such as the American Cancer Society and, in part, by the willingness of physicians to follow these recommendations. For example, many women's health and cancer-related organizations recommend breast exams beginning at age 20 and mammograms beginning at age 40. Many groups recommend prostate-specific antigen measurement and digital rectal examination for African-American men, for any men age 40 and older who have a strong family history of prostate disease and for all men older than 50. Among the many other diseases for which screening is recommended are hypercholesterolemia, hypertension, colorectal cancer, cervical cancer, testicular cancer and osteoporosis.

Though screening guidelines are undoubtedly always made by careful consideration of several experts and with the intention to help patients, the evidence supporting screening tests is not always strong.

The U.S. Preventive Services Task Force routinely reviews the evidence that screening tests actually reduce morbidity and mortality and has compiled a list of those for which good evidence exists for recommending testing. Many more screening tests are available for which the USPSTF has found insufficient evidence to support recommendation. Of course, anecdotally, all physicians have seen patients who were helped by screening, but most of us also have had patients who sustained unnecessary harm as a result.

Before offering screening to any patient, a physician should determine whether the test meets certain criteria. Namely, the cost-benefit ratio should be favorable, the test should be easy to perform with minimal risks to patients, and it should have relatively high sensitivity and specificity.

Surpassing even these criteria is the requirement that the disease being screened for is more easily treated when detected in its early stages than after symptoms appear. And the disease must be common. A physician should consider the population in which the disease is most prevalent and decide whether the frequency of the disease in the public warrants broad screening.

In addition to test-related criteria, the physician must consider the patient's personal and family history to determine the conditions for which the patient is most at risk and, hence, which screening exams he or she should undergo.

Whether a patient ultimately agrees to undergo screening, working through the informed consent process is essential.

A patient should know what the test is for and the implications of positive and negative results. Before agreeing to undergo a PSA test, for example, a patient should understand that an elevated PSA level does not mean he has cancer but indicates that he should have a prostate biopsy. Patient education will make future visits easier for both parties and will prevent difficult situations in which a patient has a suspicious result but is unwilling to pursue a more invasive work-up.

Genetic screening presents an even greater challenge for informed consent. Recently, a male patient came to the urology office after having undergone BRCA mutation testing because of a family history of breast and ovarian cancer. The test returned a positive result, and the patient received a form letter about his risk of prostate cancer. Unfortunately, the information from the test -- and the letter -- was far too ambiguous to be of use, and the patient is now left with no definite answers and an emotional need for a lifetime of exams to rule out the possible diseases that, for him, may be associated with a BRCA mutation.

Likewise, diseases for which there are screening tests but no true treatment may or may not benefit patients. Huntington's disease is a prime example. While testing for Huntington's may not allow us to help the patient medically, it may allow him or her to prepare better for future life circumstances. On the other hand, positive test results could adversely affect the patient emotionally, psychologically or even economically by making it more difficult to obtain health and life insurance. Concerns such as these can be properly considered only by patients who are adequately informed before their consent for testing is sought.

If a physician believes screening is justified, but the patient is reluctant to proceed, the physician has a duty to explore the reasons for the patient's unwillingness. Is he or she frightened because of an experience a friend or family member had? Is there a technical misunderstanding that could be clarified with a bit of education?

After a physician has ensured that a patient's decision to decline screening is satisfactorily informed, the physician should offer alternatives. For example, a patient may refuse a mammogram, but be willing to undergo a partial evaluation by way of a breast examination. Can fecal occult blood testing with or without sigmoidoscopy be substituted for colonoscopy? Can certain preventive measures be recommended, for example, taking calcium to avoid osteoporosis, even in the absence of the screen, in this case a bone density scan?

If the patient continues to decline the screening despite understanding the rationale for the physician's recommendation, the physician should respect the decision, and carefully document the discussion and the patient's refusal.

Screening presents physicians with unique opportunities for preventive care and early intervention. But, at the same time, it requires serious thought and consideration. Physicians must be able to consider and discuss the potential consequences of screening for the patient. Above all, the physician's goal should be to inform the patient, respect his or her autonomy, and maintain a relationship in which the patient will return and will feel comfortable discussing new symptoms and concerns.

Adrienne J.K. Carmack, MD, fourth-year urology resident, University of Miami Leonard M. Miller School of Medicine; screening theme issue editor for Virtual Mentor, January