Medical screening can lead to Overdiagnosis. Unnecessary harm can occur by pursuing early screening. Overdetection identifies abnormalities that may not progress, progress slowly, or resolve spontaneously.

Overdiagnosis

Overdiagnosis, a complex issue that arises when problems are evaluated for early diagnosis as per national guidelines, underscores the need for caution in the use of medical screening. The findings detected by early screening, while potentially beneficial, can also lead to unnecessary harm. A typical scenario is that practitioners’ medicalize’ ordinary life experiences through expanded definitions of diseases. Overdetection refers to identifying abnormalities that may not progress or progress so slowly to cause symptoms or harm during the patient’s remaining lifetime or abnormalities resolve spontaneously. An example of the resolution of abnormal findings of tiny lung clots detected in tiny lung arteries in a high-resolution CT chest scan is a common occurrence. This finding does not require clot busters ( anticoagulants ), but unfortunately, too often, patients receive an ominous diagnosis of pulmonary embolism and are given anticoagulants.

Based on an elevated PSA( Prostate-Specific agent), men usually undergo prostate biopsy, and prostate cancer is found and treated with surgery or radiation therapy. Many of these prostate cancers, if left untreated and just ‘observed,’ would never have caused the death of patients- many other medical conditions like a heart attack or stroke would likely cause death long before prostate cancer advanced.

Thyroid cancer is the most common endocrine malignancy. 90% are papillary thyroid cancers (PTC).  Papillary thyroid microcarcinoma (PTMC) is a small thyroid malignancy measuring ≤1 cm. Thyroid cancer was vastly overdiagnosed in South Korea when practitioners used thyroid Ultrasound to screen for thyroid nodules. From 1999 to 2008, the incidence of thyroid cancer increased 6.4-fold, but 95% of these cancers were small (<20 mm).  In South Korean women, thyroid cancer incidence changed from 10.6/100,000 in 1996 up to 111.3/100,000 in 2010. The mortality of thyroid cancer in South Korea remained unchanged during this period, and many of these small cancers would never have led to advanced cancer and harm and yet got unnecessarily treated ( surgical removal and replacement lifelong thyroid medications ). Healthcare experts noticed similar thyroid cancer screening tests in China.  There is a large geographical variability in thyroid cancer diagnosis across the country. Urban areas and cities have a much sharper increase in thyroid cancer diagnosis than in rural areas of China. Almost certainly, this is due to the easy availability of Ultrasound imaging of the thyroid gland in urban areas. It is essential to point out that there is no corresponding increase in mortality from thyroid cancer in geographical areas reporting a high incidence rate of thyroid cancer. Other developing countries should heed cautionary tales from South Korea and China regarding the overuse of imaging (Ultrasound ). They can design and implement policies to discourage large-scale use of screening thyroid ultrasound studies.

Overdefining risk factors, such as lowering the systolic blood pressure (SBP) goal from 150 mm to 130 mm, can have serious consequences. This shift, made without robust evidence of improved prognosis, leads to more patients receiving medications to reach the lower goal. As a result, these patients may experience side effects, with no actual benefit in outcomes. 

American Diabetes Association has enabled an epidemic of “pre-diabetes” by lowering the threshold of A1C ( Glyco-hemoglobin, which gives an average of all blood sugars in a patient during the previous three months ). A reading over 6.5% indicated Diabetes. As per ADA and CDC, a level between 5.7% and 6.4 % is in the prediabetic range. ADA states that 5% to 10% of those with pre-diabetes develop Diabetes every year, and therefore, these people should be treated with lifestyle changes and drugs if need be. Other experts have assessed the risk of Diabetes at only 2% per year. A comprehensive review of 103 studies by the Cochrane Library in 2018 showed that most people who qualify as prediabetic never progress to Diabetes over any period studied, and according to the review, up to 59% of prediabetic patients returned to average glycemic values over 1-11 years with no treatment whatsoever. What widespread publicity of pre-diabetes has done is to medicalize a large number of healthy people into monitoring their blood sugars at home, by having six monthly A1C monitoring and ,by using diabetes medications with questionable benefits; there is almost certain medical harm of low blood sugar reactions from diabetic medications, psychological damage and financial harm from prescription drug costs.

It is not uncommon that abnormalities in other anatomic areas are reported by radiologists when, for example, CT scans for a chest condition, which includes those taken in the abdominal area, reveal abnormalities like a nodule (small lump called an adenoma) in the adrenal gland ( gland just over the kidney). In some instances, radiologists report a mass in a kidney. These abnormalities are termed incidentaloma, an incidental or unanticipated finding. What was previously unknown would never have come to light for most patients with findings of incidentalomas- including kidney cancer since patients would never have experienced any symptoms in their lifetime.! Once radiologists report an abnormal finding, further testing, including invasive biopsies, follows, and in some instances, surgeries. 

Most people, at times, have experienced sadness, difficulty sleeping, and difficulty focusing. Practitioners misdiagnose patients with clinical depression, insomnia, and Attention Deficit Hyperactivity Disorder ( ADHD) and prescribe medications with harmful side effects. Then there is disease mongering  with high-pressure advertisements for conditions of low testosterone associated with aging( Low T  syndrome ), restless leg syndrome, and chronic dry eye syndrome, for which  expensive prescription medications are recommended ( Ask your doctor for an  Rx !) 

Reference: BMJ Evidence-based Medicine Vol 23 Issue 1, 2017