Informed consent for prostate-specific antigen screening

Prostate-specific antigen (PSA), the first circulating tumor marker to be mass marketed by commercial interests and to gain widespread acceptance by physicians and the public,1 is now in general use as a screening test for the detection of asymptomatic prostate cancer. It is estimated that approximately 30% of men in the Medicare population undergo PSA screening regularly.2 Much of this testing—perhaps 30%3—occurs without patient knowledge when blood chemistry panels are ordered as part of routine health evaluations. Recognizing that PSA screening is inexorably linked to invasive testing (prostate biopsy) and/or prostate cancer treatment (ie, radiotherapy or surgery), if PSA elevations or prostate cancer is discovered, should informed consent be obtained before PSA screening?

The reasonable person standard of informed consent holds that physicians should disclose the information that a reasonable person needs to know to make an informed decision.4 For a controversial screening test such as PSA, the information to be disclosed before PSA screening has not been defined and will differ depending on the expertise of the physician and the perspective of the patient.5 Given the uncertainty surrounding PSA screening, there is a strong rationale for communicating (verbally and/or by pamphlets, video, etc.) the nature of the test and the risks and benefits before obtaining the test. This is a concept endorsed by the American Urological Association,6 the American Cancer Society,7 the American College of Physicians, and the American Society of Internal Medicine,8 although no guidelines regarding what information should be communicated to patients are available. So what should men know?

I believe the information that men should know before PSA screening can be broken down into information about prostate cancer, the PSA test, and the possible downstream outcomes after PSA screening.

Prostate cancer 

First, with respect to prostate cancer, a man should know that the risk of prostate cancer increases with age, a positive family history, and African-American race. Second, he should know that in the absence of PSA screening, men who die with a diagnosis of prostate cancer most often die of prostate cancer rather than another cause.9 Thus, prostate cancer represents a serious threat to life when the diagnosis is made in the absence of screening. Third, he should know that the current incidence and mortality data demonstrate that the risk of death from cancer in those diagnosed today is similar for prostate and breast cancer, the difference being that the burden—in terms of mortality—for prostate cancer is heavily weighted toward the end of life.10 Fourth, that because of the slow progression of the disease, the risk to life is far greater when the diagnosis of prostate cancer is made at a younger age compared with a diagnosis of prostate cancer in an older man11—especially those older men with serious comorbidities that have been shown to reduce the length of life (cardiovascular disease, diabetes, obesity, etc.). These data help put into perspective the fact that prostate cancer is a serious health issue in the aging man.

PSA test 

With respect to the PSA test, men should know that it is a blood test for prostate cancer detection that, when used in conjunction with a digital rectal examination, leads to the detection of prostate cancer earlier than if a digital rectal examination had been used alone. Earlier detection leads to discovery of cancers that are more likely to be treated successfully. Second, most men who have abnormal PSA tests do not have cancer and thus most men will undergo further testing (biopsies) unnecessarily. This can lead to future concerns in the years to come about abnormal tests, and the possibility of missed cancer, because prostate biopsies are an imperfect method of identifying the disease. Third, PSA screening has not been shown to be effective (to reduce overall prostate cancer deaths)—but it has not been proved to be ineffective either. Thus, the use of the PSA test for prostate cancer detection is controversial at present. Fourth, all screening tests for cancer (including PSA) can lead to the detection of tumors not destined to cause harm, and physicians are currently unable to reliably identify after diagnosis—in most cases—which prostate cancers are life threatening. Thus, the potential for unnecessary treatment after diagnosis that will add no additional years to life is a major concern, especially among older men. However, PSA screening can detect life-threatening cancers for which treatment may add additional years to life.

Downstream outcomes after screening 

With respect to the possible downstream outcomes after PSA testing, men should realize that an abnormal PSA test usually leads to the performance of one or more prostate biopsies, an imperfect test for excluding the presence of prostate cancer. Second, that a diagnosis of prostate cancer is followed by the need to make difficult choices between treatment and no treatment, and that various treatment options are available from which to choose for those who choose treatment. Third, as with any cancer treatment, there is the potential for the reduction of quality of life—especially in the areas of urinary, sexual, and bowel function after treatment for prostate cancer.

Conclusions 

Some physicians will believe that time does not allow this type of communication, given the demands placed on healthcare professionals today and/or that patients are unable to understand the complexity of the issues surrounding screening. I believe that to help individuals make difficult choices—in the face of unknowns—that coincide with their personal interests, and not the interests of the physician, is what distinguishes us from other “professionals.” It is in our best interest to ensure that this distinction remains clear.