Public screening programs are commonplace. Medical students are often encouraged to participate in providing such programs and many continue to contribute to this type of activity throughout their medical careers. Programs such as cholesterol checks at the mall, breast exams and mobile mammography units, and prostate cancer screening with digital rectal exams on site and laboratory testing for prostate-specific antigen levels (with results mailed to the screened individual) are examples of public screening programs. Unfortunately, following up with the patients who undergo public screening programs is extremely difficult, and no evidence-based guidelines for these types of programs exist. Given this lack of data, and the implication of screening results, those who participate in public screening should give thorough consideration to several points. Screening outside of a clinic setting poses unique challenges; the responsibilities incurred in this setting differ significantly from those physicians commonly encounter.
One goal of physicians is to prevent disease. Screening may allow us to do so, or at least to identify disease at a stage in which it can be treated more effectively. The goal of a public screening program is to search for disease in populations that are at high risk by using minimally invasive tests to detect disease or risk factors before symptoms develop. The intention is, of course, that once the patient is diagnosed, he or she will seek medical care elsewhere to treat whatever abnormality or risk factor is discovered. Screening is a short-term clinical encounter for what will prove to be a long-term intervention for any patient with positive results.
The most obvious challenge of public screening lies in the nature of the patient-physician relationship. The interaction with the physicians, medical students, or other health care professionals who conduct the screening is necessarily brief. A full history and physical is rarely, if ever, done, limiting the physician's ability to counsel patients in a personalized manner. Often, test results are not available on-site. With prostate cancer screening programs, for example, patients undergo one on-site test (a digital rectal exam) and then wait for the serum prostate-specific antigen measurement results to come in the mail. It would be rare, then, for the physician who conducts the screening exam to identify potential patients; it is more likely that individuals being screened already have physicians to whom they will report their results or that they are un- or under-insured and hence unable to get routine care. If a potentially serious diagnosis is uncovered during a screening test, a person whom the individual has just met must deliver the diagnosis and somehow ensure that the recipient of the news will have follow-up care, usually from another physician in another setting.
It is also necessary to step back and look at screening in the context of the limited access to health care that characterizes our system in the US. Those individuals who cannot afford health care may be unable to seek care for any condition that the screening uncovers. It is critical that those organizing screening programs make sure before screening takes place that the appropriate follow-up tests and physician visits will be available to those who need them. Screening in and of itself does not serve to help any one patient; the benefit comes from receiving effective care after results are known.
Another ethical challenge in public screening is ensuring informed consent. Often a person is shopping in a public place when he or she sees an offer for a free medical test and decides to participate. Even though performing the test is easy, the person tested is done a disservice if he or she is not fully counseled about the intentions of the test (what it really can show), the implications of positive or negative results, and the need for follow-up studies in the case of certain findings. Anyone who expresses an interest in a public screening program should be given this information and required to sign a written consent form that outlines them.
Ultimately, our intentions are to help the public while respecting the principles of beneficence and nonmaleficence. Anyone who does not understand the test, cannot obtain follow-up care, or is inappropriately diagnosed or counseled because of the lack of a patient-physician relationship does not benefit from the test.
The major, sustainable benefit of public screening lies in education. Only by educating our patients can we ensure that the real goal of screening will be met after the brief testing encounter. It is more important to inform patients about the existence of a test and ways that they can obtain medical care than it is to actually perform the test in the restricted environment with the myriad challenges just described. Patient education should be the primary goal of all public screening programs if we wish to maximize our potential to improve the lives of our patients and the public.