Informed consent for prostate-specific antigen-based screening

Should there be a consenting process for prostate cancer screening?” is an excellent question. A number of expert organizations have commissioned studies of prostate cancer screening data and provided varied and conflicting recommendations.1, 2, 3 Some recommend that screening be done, some that screening be offered, some that screening not be done.

In discussing the issue of consent, I would draw a difference between the patient seeing a physician and a subject being offered screening in a screening program. Screening of large numbers of persons in a “program” is often referred to as “mass screening” in lay terminology; and epidemiologists specializing in screening refer to it as “opportunistic screening.” I do not believe explicit consent concerning screening is necessary within the physician–patient relationship. However, I do believe it should be done very carefully in opportunistic or mass screening.

When a patient goes to see a physician, that patient contracts with the physician for that physician’s knowledge and opinions. I believe that by going to the physician and allowing the physician to see them, patients are consenting to minor procedures that are necessary or reasonable in the opinion of the physician. The physician can surmise what is appropriate and what is inappropriate for this patient given their health status and other concerns. In this sense, I do not believe that prostate cancer screening, which I would describe as a minor procedure, requires a more formal consent or an informing process.

Although I believe that informed consent is not required in the physician–patient encounter, I would hope that the physician would, at least briefly, mention prostate cancer screening. I am very supportive of statements from the American Cancer Society2 and the American Urological Association3 stating that men should be offered the test and informed of the potential risks and potential benefits of the test and the treatment resulting from it. I would also hope that physicians who hold the opinion that screening is inappropriate would also discuss the procedure with their patients and provide screening for those who want it.

In terms of the potential risks and benefits, the physician need only mention that screening has not been proven to save lives and its use is controversial. The caregiver can, if time permits, go further, noting that it is controversial among respected expert medical organizations. It may save lives, but it also can diagnose men with the disease who do not need treatment and can lead to needless treatment. Most patients will accept the procedure if the physician recommends it. Some will want further discussion. I believe a signed consent form is unnecessary within the physician–patient encounter, although to save time, the physician may want to have a prepared written statement on prostate cancer screening.

The only hesitance in my belief that a physician need not obtain written informed consent for screening is that I have found that a number of physicians (even noted urologists) simply do not understand the basic principles of cancer screening. The urologic literature has numerous statements that screening must be effective because the proportion of men surviving 5 years has increased or because distant disease at diagnosis is now rarely seen. These statements do not prove that screening decreases mortality and saves lives. They ignore facts that support caution in the advocacy of screening. First, cancer screening can cause survival to increase dramatically, without mortality changing or even increasing. Survival can increase because of length bias and overdiagnosis. By overdiagnosis, one means the diagnosis of cancer that although pathologically clinically significant, is not clinically significant to the particular man with the cancer. The patient would have lived without the tumor ever bothering him. Population survival was increased and mortality did not decrease among participants in the randomized trials of lung cancer screening trials with chest radiography and sputum cytology versus no intervention in the 1960s and 1970s.4 Indeed, in the Mayo Clinic study of lung cancer screening, the lung cancer death rate after 20 years of follow-up was 4.4 deaths (95% confidence interval 3.9–4.9) per 1000 person-years in the intervention arm and 3.9 deaths (95% confidence interval 3.5–4.4) in the usual-care arm (two-sided P for difference = 0.09). This phenomenon was also seen in children in the study of neuroblastoma screening in the 1990s.5, 6 In neuroblastoma screening, a number of children received unnecessary major surgery with significant comorbidity. Comparisons of populations in which the prevalence of screening is high with populations with a lower prevalence of screening showed widely varying incidences with very similar mortality rates, suggesting that overdiagnosis is a real problem in prostate cancer.7, 8 Perhaps 40% or more of men who are diagnosed with localized disease do not benefit by being diagnosed because the tumor would never have bothered them.9, 10 Incidentially, the populations with less screening and a lower incidence showed a decline in mortality in the 1990s very similar to that attributed to screening in the high-screening areas.

That American men are rarely staged as having distant disease at diagnosis today must be interpreted carefully. In population studies, more than one third of all American men undergoing radical prostatectomy develop relapse after surgery. A substantial proportion (24%) of men receiving radical prostatectomy for pathologically localized disease at diagnosis ultimately develop relapse according to prostate-specific antigen testing.11, 12 This indicates that these men were actually under staged at diagnosis and truly had extraprostatic disease at diagnosis.

In the instance of mass or opportunistic screening, I believe strongly that there should be careful teaching and informed consent and there should be signed informed consent. Many of the organizations that make recommendations regarding early detection (as done in a physician–patient relationship) have not looked so favorably on mass screening. The American Cancer Society has even recommended against mass screening of men at normal risk.2

There are also some public health and ethical principles that one must consider when discussing mass screening. One of the principles of public health is that interventions should not be advocated until they are proved effective. For example, public health officials have been hesitant to advocate widespread use of a vaccine without as full an evaluation beforehand as possible. Prostate cancer screening would be effective if it reduced prostate cancer mortality. A well-designed randomized study must be completed to show this.

The offering of a mass screening intervention without the provision of accurate information implies a benefit will be rendered to those screened. I do not believe the current evidence so clearly shows a benefit. Another ethical issue that must be dealt with in mass screening is that I or anyone with medical business savvy can estimate with good accuracy how much money a healthcare institution can make from offering free prostate cancer screening, but no one is able to estimate the number of lives that would be saved from such mass screening.

Indeed, previous awareness and screening campaigns have demonstrated that by offering free screening to normal-risk American men older than 50 years of age who volunteer, approximately 15% will have an abnormal prostate-specific antigen test and approximately 4% to 5% will be diagnosed with prostate cancer.13 These studies have even demonstrated that the overwhelming majority will have health insurance to pay for their evaluations and treatments. I am further troubled that I can even make good estimates of the treatments received by the 4% to 5% with prostate cancer.14, 15 I can make good estimates of the number who will have an untoward side effect of therapy and the number who were treated and did not actually need treatment.16, 17, 18 All this, but I cannot provide an estimate of the number of lives saved.

This is not a piece against mass screening, it is a plea that those offered screening in community screening and awareness campaigns be informed of what is scientifically known, what is not known, and what is believed about prostate cancer screening. Although some of the pro-screening statements and even studies published in the urologic literature are nonsense to epidemiologists specializing in screening, sound data do exist to suggest that prostate cancer screening may decrease mortality. A reasonable person with proper expertise can read the published reports and rightfully conclude that screening likely does save lives. Unfortunately, strong data show that screening leads to a good proportion of men being diagnosed who do not need to be diagnosed. This in turn causes many of these men to receive unnecessary treatment and unnecessary side effects. Ultimately, the truth is that the effectiveness of screening will be open to debate for some time. This means that although the harm to the man screened are well defined, as are the benefits for those who treat prostate cancer, the benefit to the man screened is less well defined. The advocacy of mass screening without the advocacy of informed consent is troubling.