Ecological studyindependent cross-checkabstract checked★ key study I-ORG-112 in-depth review
US thyroid cancer trends 1974-2013
Trends in Thyroid Cancer Incidence and Mortality in the United States, 1974-2013.
Overview
Lim H et al.. JAMA 2017 · PMID 28362912 · DOI 10.1001/jama.2017.2719
Thyroid cancer diagnoses tripled; deaths rose only slightly, mainly from advanced cancers.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Check whether rising thyroid cancer diagnoses reflect a real increase
- How was the study done?
US cancer registry analysis
- How many people, animals or samples were studied?
77,276 patients
- What was actually found?
Incidence tripled; small rise in mortality for advanced disease
- How large was the observed effect?
Mortality +1.1% per year
- What do the results mean in everyday life?
Most new cases are small, but some real increase exists
- What are the study's limitations?
Registry data only
- What does it say about Elawady's specific claim?
Mostly supports overdiagnosis, with a caveat
- Do the results apply to Germany and Europe?
Similar patterns in Europe
- What can explicitly not be concluded from this study?
Cannot say which individual cancers need surgery
Scientific in-depth review
1. Full reference
- Authors
- Lim H et al.
- Journal
- JAMA
- Year
- 2017
- Identifier
- PMID 28362912 DOI 10.1001/jama.2017.2719
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
NIH intramural research (PubMed).
2. Research question
Have increases in papillary thyroid cancer incidence been accompanied by changes in thyroid cancer mortality?
3. Study design and population
- Study design
- Ecological study – Registry-based trend analysis (SEER-9), incidence and incidence-based mortality by histology and stage
- Population
Patients diagnosed with thyroid cancer in SEER-9 areas
- Country
USA
- Period
Diagnoses 1974-2013; deaths 1994-2013
- Sample size
77,276 patients; 2371 thyroid cancer deaths
- Inclusion and exclusion criteria
SEER-9 registry cases
4. Methods and endpoints
- Exposure / intervention
Calendar period; tumour characteristics
- Comparator
Earlier periods
- Endpoints
Age-adjusted incidence and incidence-based mortality
- Statistical methods
Annual percent change by log-linear regression
5. Actual results
- Results
Incidence increased 3.6% per year (95% CI 3.2-3.9%) from 4.56 to 14.42 per 100,000 person-years, mainly papillary cancer (APC 4.4%). Papillary incidence rose for all stages, including distant stage (2.4% per year). Incidence-based mortality increased 1.1% per year (0.6-1.6%) from 0.40 to 0.46 per 100,000 and 2.9% per year (1.1-4.7%) for distant-stage papillary cancer.
- Absolute risks
Incidence about tripled (4.56 to 14.42 per 100,000); mortality 0.40 to 0.46 per 100,000.
- Authors' conclusion
Increases in incidence and mortality for advanced-stage papillary thyroid cancer are consistent with a true increase in thyroid cancer occurrence in the US.
6. Strengths
- Long registry series
- Stage-specific analysis
7. Weaknesses
- Ecological
- Incidence-based mortality small numbers
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- not assessable
- Rationale
Population registry analysis.
9. Assessment of the statistical interpretation
Incidence tripled (ratio 3.16) while mortality rose only 15% in relative terms and 0.06 per 100,000 in absolute terms (stats/C-ORG-14_15_thyroid_cs.py).
10. Relevance to the specific claim
Main counter-argument: part of the rise is a real increase, not only overdiagnosis.
11. Independent contrary findings
Li 2024 (I-ORG-113) and Davies 2014 (A-ORG-19) attribute most of the increase to overdiagnosis.
12. Transferability to Germany and Europe
US data; European countries show similar but variable patterns.
13. Overall methodological judgement
Refines rather than refutes the overdiagnosis claim: most of the rise is small cancers, but a small true increase in advanced cancers and mortality also exists.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | not assessable |
| Precision of results | high |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Causes of the true increase (e.g. obesity, radiation).
15. Linked fact checks
- Thyroid cancer diagnoses tripled (US 1975-2009) while mortality stayed flat — an epidemic of diagnosis (overdiagnosis), driving avoidable thyroid surgery. – Studies contradicting or limiting the claim