Oncology ·
Proposed TNM System Improves Prognostic Stratification in Poorly Differentiated Thyroid Cancer
An international cohort study developed and externally evaluated a TNM staging system specific to poorly differentiated thyroid cancer (PDTC). The proposed system showed better discrimination for overall survival than TNM-8 in the development cohort, although the improvement in the SEER validation cohort was uncertain.
- Study included 1,010 international cohort and 170 SEER patients.
- Level VII nodal metastasis was classified as N1c.
- Discrimination improved in the development cohort.
- External validation showed an uncertain improvement.
PDTC has no dedicated staging system and is currently staged using the eighth edition of the American Joint Committee on Cancer and Union for International Cancer Control TNM system for differentiated thyroid cancer. This cohort study analyzed surgically treated patients from 91 centers in 14 countries: 1,010 patients in the International Aggressive Thyroid Cancer Collaborative Group cohort and 170 in a US Surveillance, Epidemiology, and End Results (SEER) validation cohort. Overall survival was the primary endpoint.
The proposed system reclassified level VII lymph node metastasis from N1a to N1c, reflecting its association with lower five-year overall survival than level VI or lateral neck nodal disease. Compared with TNM-8, the new system had a higher C statistic in the development cohort (0.74 vs 0.71; difference, 0.03; 95% CI, 0.01-0.04). In SEER, the corresponding values were 0.76 and 0.74; the difference was 0.02 (95% CI, −0.01 to 0.06).
The findings support further consideration of a stand-alone PDTC staging system, but do not establish its adoption in clinical guidelines. The study included surgically treated patients, and the improvement in discrimination was not statistically clear in the external validation cohort.
In practice
For clinicians caring for patients with surgically treated PDTC, the proposed system may offer more disease-specific prognostic stratification than TNM-8, including a distinct classification for level VII nodal disease. It remains a research proposal, not an established staging standard or guideline change. Although discrimination improved in the international development cohort, the difference in the SEER validation cohort was uncertain, and the evidence is drawn from surgically treated patients.
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JAMA Oncology: Global Proposal for the TNM Staging System for Poorly Differentiated Thyroid Cancer ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.