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Early Detection—What’s In It for You?

Part of an occasional series on new health information.

Something very interesting appeared in the January issue of the medical journal, Urology. It was a panel of eight editorials discussing the pros and cons of informed consent for prostate-specific antigen (PSA) screening (a widely-used blood test).

The authors were 10 physicians, experts from cancer and urology centers at major medical institutions. They did not all agree about having individuals give formal informed consent before undergoing prostate-specific antigen screening. But they all acknowledged the considerable controversy surrounding prostate cancer screening that has divided the medical community.

Screening has not been proven to reduce overall deaths from prostate cancer, though some of them believe it does. “Valid arguments can be made to recommend for or against this test,” said one author. Is there, overall, more benefit or more harm from screening for prostate cancer? This attention given to informed consent by the journal underscores the uncertainty and the debate, with experts on both sides.

That early detection of disease leads to more successful treatment is a strongly held belief in our society and healthcare system. The tradition of periodic checkups that many of us grew up with is based on the potential benefit of finding a problem before it becomes overtly apparent, and hopefully while it’s more treatable. When I talk with people about the value of screening information, they often ask, “Well, why wouldn’t you always want to know?” Our intuition tells us that knowing is better than not knowing, earlier is better than later and treating is better than not treating. It seems like common sense. It reassures us that we have some defense against dreaded conditions.

So it’s no surprise that screening to uncover hidden disease, especially cancer, enjoys widespread popularity among consumers, providers, policymakers and even payers. Technology helps out by offering increasing opportunities to look for occult disease. Screening seems the path to extending and “saving” lives.

However, while it’s intuitively very easy to accept the idea that finding hidden disease lengthens life, it just hasn’t been easy to demonstrate that it is really true. Actually, there has been controversy about the value of screening for decades. Years ago, this was studied in part because HMOs were interested in whether screening could improve the health of their subscribers and decrease the costs of care. Results actually revealed fewer benefits than anticipated. Reality clashed with intuition. This clash continues today. Besides the prostate cancer issue, there is no proof that screening reduces lung cancer deaths, even among high-risk individuals such as smokers and with follow-up as long as 25 years. Questions remain about the effect of screening mammography on breast cancer mortality. Definitive proof that early detection helps is scarce.

Why would the journal, Urology, devote over 20 pages to the issue of informed consent for PSA screening? Informed consent is generally utilized when a person is about to undergo an intervention that carries some risk of significant adverse outcomes that he or she should be aware of. PSA screening for prostate cancer is a simple blood test in use since the 1980s and widely recommended.

Where’s the risk? The risk might be that the test is the first step along a path leading to the possibility of more harm than good. Many feel that, until definitive evidence of net benefit or harm is available, individuals should be educated about the possible consequences before the test is performed. Once an undesirable PSA level is found, it is hard to stop the subsequent cascade of events, particularly with the specter of cancer hanging in the air. Some people are also concerned about how frequently PSA testing is done without the person’s knowledge at all, as in a routine checkup or an employment or insurance exam.

There may not be a simple answer to the question, “Is there net benefit or net harm?” It may depend; individual risk varies. The first step is recognizing that this is not simple and that there are potential pitfalls to doing the test. Then you can explore it to your level of satisfaction before going ahead. I’ll give you some sources in a future column.

Mark H. Zweig M.D., previously a staff physician at NIH, has more than 35 years of experience in medical research and 25 years in patient care, with particular interest in medical decision-making and preventative medicine.