Opportunistic testing: the death of informed consent?

Author:Davis, Dena S.
Position::New Technologies, New Challenges: Women and Prenatal Genetic Testing in the 21st Century
 
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ABSTRACT

This Article focuses on one aspect of prenatal diagnosis: noninvasive prenatal diagnosis, particularly the detection of Trisomy 21 (Down Syndrome) through a simple test of maternal blood. Although I discuss issues salient to this particular test, I place it in the context of "opportunistic" testing generally. It is my view that opportunistic testing presents the most serious challenge to patient autonomy we are facing in the twenty-first century. In this Article, I will explain what I mean by opportunistic testing (1) and consider three different examples of how it threatens informed consent: (1) Prostate-Specific Antigen (PSA) screening, (2) newborn screening, and (3) prenatal diagnosis of maternal blood tests for fetal anomalies.

CONTENTS I. OPPORTUNISTIC TESTING II. PSA SCREENING III. NEWBORN SCREENING IV. NONINVASIVE PRENATAL DIAGNOSIS V. CONCLUSION I. OPPORTUNISTIC TESTING

Opportunistic testing or screening is medical testing that makes use of an "opportunity" engendered by some other test or modality to which the patient (2) is accustomed or has already given consent. The opportunity could be as simple as the patient presenting herself for some other reason, as in screening asymptomatic patients for an STD such as chlamydia. (3) In this context, the terra opportunistic always implies "piggybacking" one intervention onto another and thus exploiting an opportunity. It does not necessarily imply lack of transparency. An opportunistic intervention can be an obviously different event, as when patients in a general practice waiting room who had made appointments for complaints unrelated to depression were screened for depression with their informed consent. (4)

Because opportunistic interventions are, by definition, performed on patients who are presenting for a different reason, they are often associated with preventive care. (5) As prevention becomes an increasingly important medical concept and recommendations for preventive measures grow exponentially, some critics are beginning to question the dilution of focus on the patient's reason for coming to the medical setting and the imposition of risk information the patient may not want. As one commentator notes, "once information about medical risk has been passed on to a person ... it cannot be retracted. Respect for autonomy should therefore also honour the person's right not to be opportunistically confronted with knowledge about bioimedical risks that are unrelated to his or her reasons for seeing the doctor." (76)

This Article focuses on a particular subset of opportunistic testing, namely tests done on a blood sample. In this case, the blood sample is drawn for an established purpose and then one or more extra tests are added. From the patient's perspective, the intervention (a heel prick or blood draw) is exactly the same, making it easy for a medical professional to add extra tests without the patient's consent or knowledge. If the result is negative, the patient may never know that the test was performed.

  1. PSA SCREENING

    Prostate-specific antigen (PSA) is a protein produced by the prostate gland. (7) A very small amount escapes into the bloodstream, allowing for simple testing by blood sample. (8) PSA can be used as a screening device for men not known to have prostate cancer or as a test to monitor men who have been treated for prostate cancer. (9) As H. Gilbert Welch writes,

    Like all other efforts to diagnose disease early, cancer screening is a double-edged sword. It can produce benefit: providing the opportunity to intervene early can reduce the number of deaths from cancer. It can produce harm: overdiagnosis and overtreatment. And it can do both at the same time. So while a strong case can be made for cancer screening, there are good reasons to approach it cautiously. (10) PSA screening is especially difficult to assess. On one hand, prostate cancer is the second most common cause of cancer death in men. (11) On the other hand, most prostate cancer is "indolent," causing no symptoms or harm. (12) Most men diagnosed with prostate cancer die with the disease than because of it. (13) A number of studies looked for prostate cancer in men who had died of other causes and who were unaware that they had prostate cancer. Forty percent of the men in their forties and 80 percent of men in their seventies were found to have had asymptomatic prostate cancer. (14) A common problem with cancer screening is that it cannot distinguish between three categories of cancer: (1) nonprogressive or very slow-growing cancers for which treatment is unnecessary and even harmful; (2) cancers that are so aggressive that treatment is pointless; and (3) cancers for which treatment will make a difference. (15)

    Treatment for prostate cancer is hardly harmless: substantial numbers of men who receive surgery or radiation for prostate cancer will experience irreversible impotence, incontinence, or both. (16) The European Randomized Study of Screening for Prostate Cancer, which followed men for eleven years, found that annual PSA screening for men between the ages of fifty-five and sixty-nine reduced mortality from prostate cancer by 28 percent; but when the statistics were calculated as a function of Quality of Life Years, the advantage of screening disappeared. (17) Lives prolonged were canceled out by loss of quality of life. The study found that ninety-eight men would need to be screened and five cancers detected to prevent one death from prostate cancer. (18) Of course, the other four men would almost certainly have received some form of (unnecessary) therapy with a high likelihood of being left with incontinence, impotence, or both.

    All reputable sources echo the recommendation from the American Cancer Society that men should "have a chance to make an informed decision with their health care provider about whether to be screened for prostate cancer." (19) "This decision should be made after getting information about the uncertainties, risks, and potential benefits of prostate cancer screening," and men "should not be screened unless they have received this information." (20) The National Institutes of Health website advises that the value of PSA screening is "debated" and recommends that men discuss with their doctors the reasons for and against having the test before making a decision. (21) In 2012, the independent United States Preventive Services Task Force (USPFTF) advised against routine screening for men of any age group. (22) Co-Chair Michael Lefevre explained that "for every 1,000 men treated for prostate cancer, five die of perioperative complications; 10-70 suffer significant complications but survive; and 200-300 suffer long-term problems, including urinary incontinence, impotence or both. (23) That's a lot of harm for a cancer that didn't need to be treated in the first place." (24) Even Dr. Richard Ablin, who discovered PSA in 1970, wrote in 2010 that "[t]he test's popularity has led to a hugely expensive public health disaster." (25)

    Many older men continue to be screened despite 2008 USPFTF recommendations against routine PSA screening for men older than seventy-five. (26) In fact, it is extremely common for men to be tested without their knowledge. The reason for that lies largely with the opportunistic quality of the test: men are used to having their blood screened at routine visits (e.g., for lipids), and physicians can piggyback the PSA test on top of the other tests without getting extra blood or performing any other action requiring explanation or permission.

    While that practice is indefensible, it is easy to imagine the physician's thought process, or perhaps that of the institution. To not offer PSA might lead to a lawsuit down the road. To offer it with an appropriate discussion would take time, at least fifteen to twenty minutes. (27) According to one study, the average office visit lasts 19.3 minutes. (28) Physicians and institutions may find it more efficient to give the test to everyone and save time by discussing it only in the 5 percent of cases when the results are problematic.

    An individual's decision about whether to participate in PSA screening should not be regarded as trivial. The professional who offers a test carries a considerable responsibility, because informed consent presupposes an understanding of the limitations of the program. Every test carries a chance of misclassification of disease and false positive results that can lead to further, potentially harmful interventions. In addition, negative results can give false reassurance.

    Furthermore, patients and doctors tend to make different choices depending on the way statistical estimates of potential medical benefit are presented. While "a fifty-five-year-old man may, for instance, be interested in an 18 percent reduction in the relative risk of dying from colorectal cancer" with screening, he may be "more reluctant if told that screening implies an absolute risk reduction of only 0.014 percent a year." (29) Alternatively, he may "consider that the likelihood of not dying from colorectal cancer is 99.34 percent if you are screened and 99.20 percent if you are not screened. Unless the doctor is willing to solve this information dilemma by using a simple paternalistic reminder such as, 'take the test, it is good for you,' many preventive interventions seem too complex to suit the model of opportunistic health promotion in the general practitioner's office." (30)

    Considering the controversy swirling around PSA testing, it is outrageous that so many patients are subjected to it without their knowledge or consent. It is difficult, however, to document what percentage of patients is given the opportunity to make an informed choice before engaging in PSA testing. In 2010, researchers in the United Kingdom reported that only about a third of 106 men given a PSA test were aware of such basic facts as the goals of the test and the likelihood that it would lead to...

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