After introduction of a thyroid cancer screening programme, many screen-detected papillary microcarcinomas are surgically resected. Follow-up studies show these lesions would never have grown or caused symptoms during the patients' lifetimes had they remained undetected. The phenomenon of identifying such indolent pseudodisease is termed:

• A Recall bias
• B Length-time bias
• C Misclassification bias
• D Overdiagnosis ✓

Explanation

Overdiagnosis is the detection of lesions that meet pathological criteria for cancer but would never progress to clinical disease; it inflates apparent incidence and leads to unnecessary treatment. It is closely related to but distinct from length-time bias, which is the preferential detection of slow-growing lesions by the interval between screens. Recall bias is a data-collection error irrelevant here.

Reference: Park's Textbook of Preventive and Social Medicine, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.