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Preventive Care: When anecdotal effectiveness fails to translate

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photo credit: Keenen Brown via photopin cc

By: Katherine Donigan

It’s been over forty years since President Nixon signed the National Cancer Act, effectively inaugurating the “war on cancer.”  In this time, many advancements have been made to further our understanding about the initiation and progression of many different types of cancers.  Significant progress has been made in the treatment of specific types of cancer (particularly childhood leukemias), however cancer remains a leading cause of death worldwide (i).  Our increased knowledge about the progression of cancer from primary tumor formation to advanced metastatic disease has underscored the importance of early detection through preventive screening.  Preventive screening aims to identify tumors at early stages before they have the opportunity to invade surrounding tissues and form satellite tumors (metasteses) throughout the body.  Catching cancer in these early stages is crucial, as the majority of cancer-related deaths are attributed to metastatic disease.  Therefore, it seemed logical that more screening would result in fewer deaths from cancer.

In 1984, the U.S. Preventive Services Task Force (USPSTF) was established by Congress to objectively evaluate existing scientific data regarding the effectiveness of preventive screening tests, medications and/or counseling (ii).  The USPSTF is comprised of primary care providers with expertise in evidence-based medicine and preventive care.  Recommendations provided by the USPSTF have mainly been used by physicians when determining whether to order preventive screening tests or medications. Insurance companies have been increasingly looking to the USPSTF recommendations to inform coverage decisions.  Medical societies also utilize task force findings to generate clinical guidelines for their members.  The USPSTF recommendations are therefore extremely far-reaching, as they inform both doctors who order tests/medications and insurers who pay for them.

The recently enacted Affordable Care Act (ACA) includes a preventive care provision, seeking to “help make prevention affordable and accessible by requiring health plans to cover recommended preventive services without charging a deductible, copayment or co-insurance” (iii).  The ACA defines “preventive care” with a specific list that includes services such as immunizations and screening for certain types of cancer.  The ACA requires these services to be covered at specified intervals and age thresholds based upon USPSTF recommendations (iv).

However, when these recommendations conflict with those supported by various medical societies, what metric should be used to define what is covered and what isn’t?  For example, such differences are seen in the use of mammograms to detect early stage breast cancer.  The American Cancer Society (ACS) advises women to receive a mammogram annually at age 40 and to continue receiving mammograms regardless of advanced age (v).  In contrast, the USPSTF only recommends mammograms every two years for women aged 50 to 74, with earlier screening possible depending on patient history.  The National Cancer Institute (NCI) recommends that women over 40 have mammograms every 1 to 2 years unless known to be at high risk (vi).

Conflict is also apparent regarding the issue of breast self-exams.  The ACS promotes breast self-exams starting at age 20 and continuing throughout life, whereas the USPSTF actually recommends against teaching women how to perform these exams.  The NCI refrains from taking a position on breast self-exams, noting that while some women may choose to perform them, clinical trial data indicate that they do not reduce cancer-related deaths.

Presented with the available data, each group arrived at different conclusions when weighing the benefits of early detection against the harms of false positives that may lead to unnecessary tests and biopsies.  Unreliable tests may give a positive result indicating the presence of cancer when in fact, no cancer is present.  When completely healthy people are given a cancer diagnosis, they are sent down a path of anxiety and stress worrying about a nonexistent condition.  They will likely be subjected to further unnecessary (and costly) testing, surgeries and perhaps even chemotherapy or radiation treatments.  Indeed, a recent Norwegian study indicates that overdiagnosis resulting from mammogram screening occurs in up to 15-25% of detected breast cancer cases (vii).

Similar ambiguity in the need for screening advisories exists regarding cervical cancer, as many doctors perform Pap tests as part of an annual gynecological exam (viii).   Many women have become accustomed to the annual Pap test and while some will be relieved to be subjected to less frequent testing, others may feel anxious that their doctors might be “missing something”.  Every year, 50 million women in the United States get a Pap test and approximately 2 million receive an abnormal result (ix).  Most patients with abnormal tests go on to have subsequent normal test results, however for the minority that receive further treatment to prevent cervical cancer progression, an annual test could be life-saving.  Such anecdotes can leave powerful impressions with both patients and doctors, as annual screening remains prevalent despite recommendations from the ACS (dating from 1987), and more recently, the USPSTF and the NCI, indicating that testing is only advised every 3 years.

    Some screening tests have actually received recommendations against any use due to high rates of false positives.  In the United States, 20 million men are screened annually for prostate cancer using the prostate-specific antigen (PSA) test.  However, there is no provision for the PSA test outlined in the ACA – a decision based on USPSTF findings.  In October 2011, the USPSTF issued a recommendation against PSA testing in healthy men regardless of age – a change in position from 2008 when PSA testing was only discouraged in men over age 74 (x).  A recent literature review published in the journal Gerontology indicates that PSA testing leads to overdiagnosis and unnecessary treatment (xi).  The ACS issued a more conservative statement, recommending that men over 50 discuss benefits and harms of PSA testing with their doctor.  Shortly after the USPSTF issued their guideline, the American Urological Association came out in favor of the test, indicating concern that “the Task Force’s recommendations will ultimately do more harm than good to many men at risk for prostate cancer…” (xii).

A related conundrum exists for ovarian cancer.  Preventive screening tests, including a blood test for CA-125 antigen and ultrasounds in healthy women have been recommended against by the USPSTF, citing high rates of false positives leading to unnecessary surgical intervention (xiii).  In spite of this, a recent survey of over 1000 U.S. physicians revealed that 33% believed CA-125 screening was effective, and that more than 25% did not adhere to screening recommendations for patients at low risk (xiv).  One reason for this may be that ovarian cancer is particularly difficult to diagnose in early stages, causing patients and doctors to embrace these questionably effective screening tests “just in case”.

Passage of the ACA will undoubtedly ensure access to certain preventive care measures for millions of Americans.  However, a multitude of highly-utilized screening tests have been omitted from the list of mandated coverage provided by the ACA.  These omissions result from USPSTF recommendations advising that certain measures are ineffective or even harmful.  However, other reputable medical organizations have voiced conflicting views.  Such ambiguity can be confusing for both patients and their doctors which may lead to the resistance to altering the status quo.  Furthermore, a recent study published in Psychological Science indicates that there are several strong psychological factors that cause people to reject guidelines recommending against a long-established screening method like the PSA test (xv).  The study authors suggest that two of these factors are the power of anecdotal evidence and personal experience.

Overcoming these factors will require clear and consistent communication with both doctors and patients on the pros and cons of different types of preventive screening.   Mandating coverage of certain preventive measures by the ACA compels the evaluation of the effectiveness of those not covered and the attempt to overcome the power of anecdotal evidence.  Patient and provider education can help clarify the preventive care recommendations and reduce unnecessary, potentially harmful screening.  If insurance companies choose to restrict coverage for things like CA-125 testing to high-risk patients, people at lower risk will need to be informed about why certain tests are not useful for them. Providing patients with this information will help reduce anxiety about not being screened, or allow them to make a more informed decision if they choose to pay out of pocket.  Critical evaluation of preventive care will help reduce costs and potential harms by combating the “more healthcare is better” mentality.



Written by sciencepolicyforall

September 28, 2012 at 4:36 pm

Posted in Essays

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