# Income differences in screening, incidence, postoperative complications and mortality of thyroid cancer in South Korea

Source: https://onco.cc/key-papers/paper-kang-thyroid-cancer-overdiagnosis-income-korea-bmc-cancer-2020/  
OnCo record `paper-kang-thyroid-cancer-overdiagnosis-income-korea-bmc-cancer-2020` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Korea's thyroid cancer rate more than doubled between 2006 and 2012 and then fell by almost half by 2015 while deaths did not move, and the rise and fall were steepest among the better-off, which the authors read as evidence of overdiagnosis.

## Summary

A national time-trend study using the Korea Community Health Survey, the National Health Insurance database and Statistics Korea cause-of-death data. Age-standardised thyroid cancer incidence rose from 46.6 per 100,000 in 2006 to 115.0 in 2012 and fell to 63.5 in 2015, while mortality did not fluctuate. Higher income was associated with higher rates of screening, incidence and post-operative complications, and lower income with higher mortality; lung cancer and stroke, used as negative controls, showed the opposite pattern. The fall in incidence and complications after 2012, which the authors link to public concern about overdiagnosis, was more pronounced among high-income people.

## Fields

- Kind: Key paper
- Last checked: 2026-11-03
- Journal: BMC Cancer
- Year: 2020
- DOI: 10.1186/s12885-020-07597-4
- Authors: Kang HY, Kim I, Kim YY, Bahk J, et al.
- Findings: Thyroid cancer incidence 46.6 per 100,000 in 2006, 115.0 in 2012, 63.5 in 2015; mortality flat over the same years.; Screening, incidence and post-operative complications were all highest in the highest income groups.; The post-2012 fall was steeper in high-income groups.
- What it means: Finding more of a cancer is not the same as saving lives from it. In Korea, screening produced a surge in thyroid cancer diagnoses and operations without changing how many people died, and the surge reversed when doctors and the public questioned it.
- Caveats: Ecological trends: the study shows patterns by income, not what happened to individual patients.; Screening rates come from a self-reported survey.

## Sources

- BMC Cancer 2020: https://doi.org/10.1186/s12885-020-07597-4
- PubMed: https://pubmed.ncbi.nlm.nih.gov/33176753/

## Connected records

- key papers: [Cancer statistics in Korea: incidence, mortality, survival and prevalence in 2023](https://onco.cc/key-papers/paper-kccr-cancer-statistics-korea-2023-crt-2026/), [Korea's thyroid-cancer "epidemic"--screening and overdiagnosis](https://onco.cc/key-papers/paper-ahn-n-engl-j-med/)
- cancers: [Thyroid cancer](https://onco.cc/cancers/thyroid/)
- bottlenecks: [Overdiagnosis and false alarms](https://onco.cc/bottlenecks/b-overdiagnosis/)
- journals: [BMC cancer](https://onco.cc/journals/bmc-cancer/)

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