BY DR. EDDY LANG and ALAN CASSELS
Pandemic lockdown measures resulted in cancelled and delayed surgeries, tests and other healthcare services. Many people have suffered avoidable illness because of delays in cancer and other types of treatment.
However, media reports are delivering dire warnings that disruptions to cancer screening programs will lead to a “tsunami “of advanced breast, prostate, colon and cervix cancers and deaths. Oncologists say they’re worried that a decrease in cancer screening will lead to missed diagnoses, delayed treatment and poor outcomes like more deaths. We believe these predictions are wrong.
We have seen patients harmed by inappropriate and unhelpful screening tests such as that man who arrives in the emergency department with a dangerous blood infection from a prostate biopsy he didn’t need to have. Research has overwhelmingly shown that the PSA test – used to search for signs of cancer in healthy men – is statistically more likely to harm than confer benefit. The Canadian Task Force on Preventive Healthcare, which advises governments on the benefits and harms of screening tests, recommends against PSA screening because the likelihood of being harmed exceeds the likelihood of benefit.
Early detection of slow-growing cancers that would not go on to hurt you highlights the substantial harms associated with well-intentioned but aggressive pursuit of disease in healthy people. This is a relatively new phenomenon in medicine, known as overdiagnosis. Identifying people with a “condition” that was never going to cause them any harm, overdiagnosis converts healthy people into patients.
Cancers can be fast or slow-growing. Some cancers grow so fast that they usually show up between two rounds of screening tests. Screening often finds the slow-growing cancers or just regular anomalies that would not develop into anything dangerous. But they can lead to further investigations, treatments, sometimes chemotherapy, surgery and psychological harm.
While it is better to find potentially lethal cancers earlier rather than later, hundreds of trials about cancer screening in healthy people have consistently shown that it does not increase lifespan. The longest and best-conducted scientific trials also reveal that after many years of follow-up, patients who were screened often end up suffering the side effects of treatment but with no additional benefits. This is in comparison to those who were not screened and is true even though many people in whom indolent cancers were detected by early screening believe that their lives were saved by the test.
Prostate cancer provides a good example. With some exceptions (the United States, for example) most international guidelines recommend against testing asymptomatic men with the PSA blood test because early diagnosis does not lead to an overall survival advantage. The old saying is that most men will die with, but not because, of prostate cancer, yet the screening can cause substantial harm in healthy, older men. It often leads to biopsy-related infections, erectile dysfunction and incontinence due to surgical treatments. Sadly, these overdiagnosed patients can become critically ill as a result of infection or require long-term treatments for the complications of the treatments they underwent.
Overdiagnosis is a significant concern in nearly all healthcare fields. Discovering and labelling “abnormalities” that are unlikely to be harmful or fatal happens in the diagnosis of mental health conditions, ADHD, asthma, and allergies. Even risk factors for heart disease such as high blood pressure and pre-diabetes can result in overdiagnosis, resulting in wasteful, sometimes harmful, or unnecessary treatments. A diagnosis can lead to more tests, medications and surgeries with significant risks and long-term adverse health consequences.
COVID-19 has undoubtedly caused huge disruption and stress for both individuals and healthcare systems. Patients with worrying symptoms deserve timely assessment and diagnosis. Sometimes that assessment will involve diagnostic testing, where the doctor tries to determine the source of your symptoms and the best means to treat you. However, claims of an impending “tidal wave of deadly cancers” due to reduced screening services need to be seriously questioned. And that should not divert resources or efforts away from urgent care needs.
As the pandemic continues, researchers in Canada and around the world are studying this ‘natural experiment’ focusing on overdiagnosis. Situations that result in less overdiagnosis need to be put under the microscope, and ultimately make us re-examine some long-held beliefs that drive healthcare funding in our country.
Alan Cassels is the Victoria-based author of Seeking Sickness: Medical Screening and the Misguided Hunt for Disease.