The Mental Health Impact of Cancer Screening

Cancer is a diabolical disease that has been called the emperor of all maladies. Though treatments have improved in recent years, a full understanding of its causes and how best to treat it remains well out of reach. It is still the second leading cause of death in the U.S.

To prevent cancer deaths, many countries have for decades deployed screening programs that search for signs of cancer across an entire swath of the population, usually in age/sex cohorts. The logic is that, even in the absence of cures for a given type of cancer, you can’t hope to treat cancer if you don’t know it’s there. Cancers are also typically easier to treat when detected early.

But mounting evidence suggests that casting such a wide net across the population carries substantial risks, especially because it impacts human psychology and, in turn, our overall health.

Vinay Prasad, an oncologist and researcher at Oregon Health and Science University, has argued in numerous papers that screening may do as much harm as good at the population level. As Prasad has shown, screening seems to have some benefit in terms of preventing death from the screened-for cancer—say, prostate cancer. When you compare a large sample of people who had been screened for prostate cancer versus a sample of those who weren’t screened, the ones who were screened are less likely to die of prostate cancer. The problem is that the overall risk of death from any cause is about the same whether you are screened or not.

Prasad’s analysis draws on large and rigorous countrywide studies of screening outcomes in the U.S. and Europe, with samples comprising thousands to hundreds of thousands of individuals. In many cases, Prasad found that the value of screening in reducing overall death risk is at best debatable.

This general pattern seems to hold for common cancers such as lung, prostate, and breast cancer. What may be happening, Prasad suggests, is that the benefit from screening, which prevents some deaths of the screened-for cancer, is almost exactly offset by deaths caused by the screening itself, either directly or indirectly. Because of this, some of those who are screened seem to die from conditions that are not the screened-for cancer, conditions that they may not otherwise have suffered from. Since the goal of public health is to reduce overall risks, rather than specific risks, these findings call into question the value of current screening programs.

Direct risks from screening have long been recognized, especially for tests that involve biopsy (removing a small chunk of tissue) or radiation (chest x-ray). But what is most fascinating—and troubling—is the possibility of indirect effects. This is where psychology comes in.

A 2009 study by researchers at Harvard Medical School investigated causes of death in more than 342,000 patients diagnosed with prostate cancer. They found that, compared to the general U.S. male population, the cancer patients were substantially more likely to die from suicide and heart attack. What this seems to imply is that the diagnosis itself could prove deadly even when the cancer itself was not.

This is perhaps understandable. It is impossible for me or anyone else who has not received a cancer diagnosis to imagine the anguish a diagnosis can cause. Cancer of any kind remains a life-altering foe, despite much progress in treatment. It makes sense that receiving a diagnosis could cause psychological harm, which may in turn prove deadly.

The mental pain may lead to a greater risk of suicide. By way of stress, it may lead to a greater risk of heart attack. Though stress in adulthood has less of a causal effect on heart attack risk compared to childhood trauma or other factors like smoking and cholesterol, adult stress is now well-established as a contributor to heart attack risk. The stress of a diagnosis (as well as treatment) may be a sufficient stressor on its own, or it could exacerbate other risk factors.

Since most people with prostate cancer die from something else, this research suggests that some people may be better off not knowing if they have prostate cancer or not (though because we are talking about the population level, it is hard to know who would benefit and who wouldn’t). A small but significant number of diagnoses may also be false positives where no cancer is actually present. Prasad suggests that economic incentives may tilt medical practice toward more screening essentially so that expensive equipment such as CT scanners doesn’t sit idle as much—but this may come at the cost of the overall health of the population.

However, caveats must also be mentioned. First, the studies discussed here relate only to routine screening programs deployed across large populations, not to targeted cancer tests in those already showing signs or symptoms of cancer. I want to emphasize that if you suspect that a growth, unusual feeling, or pain may be cancer, you should absolutely consult your physician to determine if you should be tested.

Instead, the risk of screening seems to lie in its indiscriminate nature. One of Prasad’s recommendations is to make screenings much more highly targeted. National health agencies have already moved in this direction, but more specificity may be needed.

Second, these results are purely correlational and operate at the population level. We can’t say whether the extra suicides and heart attacks following prostate screening were unavoidable risks of the screening. Other factors that weren’t controlled for could be at play. Prasad advocates for studies of much larger populations in order to determine more precise estimates of the overall risks of screening programs.

But if nothing else, this area of research and debate serves to remind us how critical our mental health is for our overall health. Diseases that don’t directly affect our brains can have major consequences for our minds, which in turn affect overall health. Better scientific understanding and treatment of depression and stress may, rather surprisingly, lead to better approaches to fighting cancer.