The growing global burden of thyroid cancer overdiagnosis

A study published in The Lancet Diabetes & Endocrinology by Mengmeng Li and colleagues1 comprehensively examined the latest available data from the International Agency for Research on Cancer Global Cancer Observatory database to quantify the global burden of thyroid cancer overdiagnosis, using methods previously developed by their research team.2 Consistent with previously observed trends, the authors found that countries with the most rapid increases in thyroid cancer incidence over time were characterised by increasingly pronounced inverted U-shaped age-at-diagnosis curves (a distortion from historical patterns) and stable thyroid cancer mortality rates, which are indicative of a major contribution of overdiagnosis. Overall, the authors estimated that overdiagnosis yielded 1 736 133 million diagnoses of thyroid cancer across 63 countries during 2013–17. The proportion of thyroid cancer cases attributable to overdiagnosis was overall higher in women than men (1 368 181 [78%] of 1 757 232 vs 367 952 [68%] of 539 825) and varied substantially across countries.