Table 1.
Examples of medical conditions often overdiagnosed, by pathway to overdiagnosis
| CLINICAL INTERVENTION | DIAGNOSIS | EXTENT OF REPORTED OVERDIAGNOSIS | HARMS |
|---|---|---|---|
| Incidentalomas | |||
| • Thyroid imaging | Thyroid cancer | 75% of thyroid cancer cases in Canada have been estimated to be overdiagnosed10 | Surgery and its complications |
| • Abdominal CT | Renal cancer | The incidence of renal cancers in the United States has been reported to be related to the abdominal CT rate11 | Treatment of harmless tumours11 |
| Widened disease definitions | |||
| • Lowered target for treatment and threshold for initiating treatment | Hypertension | SPRINT reported improved cardiovascular outcomes with more intensive 120 mm Hg systolic blood pressure targets12 but with increased side effects. The intensive strategy did not achieve a net clinical benefit13 | Treatment causes hypotension and other side effects. Be cautious about extending “tight control” to patients with hypertension and perhaps restrict to those at higher cardiovascular risk |
| • Cognitive screening tests | Dementia | “The current prevalence of dementia is thought to be 10–30% in people over the age of 80, but the adoption of new diagnostic criteria will result in up to 65% of this age group having Alzheimer’s disease diagnosed and up to 23% of non-demented older people being diagnosed with dementia”14 | “Unnecessary investigation and treatments with side effects; adverse psychological and social outcomes; and distraction of resources and support from those with manifest dementia in whom need is greatest”14 |
| Screening-detected overdiagnosis | |||
| • Papanicolaou tests in women < 25 y | Cervical “precancers” that mostly resolve | 10% or more of women < 25 y have abnormal test results15 | Increased anxiety, referral, colposcopy, biopsy |
| • PSA test | Prostate cancer | 33.2% of prostate cancers were overdiagnosed in the ERSPC trial,16 and 50.4% of cancers detected by screening during the screening phase were overdiagnosed17 | Disease labeling and overtreatment, including unnecessary surgery |
| • Abdominal ultrasound | AAA | 49 per 10 000 screened men were reported to be overdiagnosed, while 2 per 10 000 would avoid death from AAA18 | Labeling; surveillance; 19 per 10 000 will have unnecessary surgery18 |
AAA—abdominal aortic aneurysm, CT—computed tomography, ERSPC—European Randomized Study of Screening for Prostate Cancer, PSA—prostate-specific antigen,
SPRINT—Systolic Blood Pressure Intervention Trial.