Disease Overdiagnosis: When Identifying Illness Does More Harm Than Good
From 1993 to 2011, the reported rate of thyroid cancer in the Republic of Korea multiplied fifteen times over. In the same period, mortality remained virtually the same (Ahn, Kim, and Welch 2014). It was not that in such a short span of time, cancer treatments had evolved to adequately deal with their increasing burden on the healthcare system in Korea, but rather a result of widespread screening programs. And the same trend is being replicated all over the developed world in an overdiagnosis pandemic. Of course, earlier detection of disease leads to better outcomes overall, but the NHS and other healthcare systems should be wary, like Icarus, of being overzealous and flying too close to the sun.
Overdiagnosis can simply be defined as diagnoses that cause more harm than good. Overdiagnosis itself can be broken down into over-detection and over-definition of disease (Brodersen et al. 2018). Over-detection refers to identifying diseases that were never going to cause any harm during a patient’s lifetime, whilst over-definition involves broadening the criteria for a patient to be diagnosed. Often, definitions for a disease are broadened due to big pharma lobbying, increasing the number of patients who will then believe they should have access to medicine – to no effect to the patients, but putting pressure on the scarce resources of national health services. Recent studies have shown that this tactic has been at the forefront of pharmaceutical campaigns – overselling ADHD is a prominent example (Sharpe 2014).
Physicians may overdiagnose in fear of the deontological and legal repercussions that could follow from failing to diagnose a sick patient. For example, there is a routine screening test for prostate cancer known as the prostate-specific antigen (PSA) test, which is subject to great controversy in the international medical community. Contrary to what the name leads you to believe, PSAs can develop not only from prostate cancer but also from many other confounding factors ranging from a urinary tract infection to riding a bike or having sexual activity before the test. Thus, a raised PSA score is not a great indicator for high-grade prostate cancer. In fact, autopsy studies have reported an overdiagnosis rate of 18.5-38.5% for prostate cancer (Loeb et al. 2014). A population stratified PSA screening program is still done in the UK, despite data proving the same mortality rates between GPs that request a lot of PSA tests and those that request none. The impacts of overdiagnosis are a large financial burden on the NHS and the significant mental-health consequences that a cancer diagnosis has in a patient’s life. Healthcare professionals should be motivated to relieve suffering, not cause it; the anxiety created by a cancer diagnosis without treatment, or health significance, goes against the principles of medicine entirely.
This is not an issue that concerns malpractice, but lifts the lid on a needed debate that should weigh on tighter control on what symptoms pharmaceuticals can list and greater emphasis on scientific precision in testing. For us all to enjoy the benefits of screening, inevitably, some overdiagnosis will persist – “chaque qualité a ses défauts”. This is the trade-off that we face: the fact that implementing screening programs is as much an economic challenge as a healthcare related one, and the opportunity costs are large. One possible solution I contend is the personalisation of screening programs: rolling out tests on a more selective invite-only basis and taking risk factors such as family history into account. With research being conducted into current UK screening programs such as the NIHR report on breast cancer, the NHS is moving in the right direction. Still, more awareness needs to be raised about the disbenefits of disease overdiagnosis to make progress in tackling what is one of today’s deepest challenges.
Photo: MedicalNewsToday
Works Cited:
Overdiagnosis and Overtreatment of Prostate Cancer doi: 10.1016/j.eururo.2013.12.062
Medication: The smart-pill oversell https://doi.org/10.1038/506146a
Overdiagnosis: what it is and what it isn’t http://dx.doi.org/10.1136/ebmed-2017-110886
Overdiagnosis and overtreatment of prostate cancer DOI: 10.1016/j.eururo.2013.12.062