Endocrinol Metab.  2017 Dec;32(4):434-441. 10.3803/EnM.2017.32.4.434.

Disease-Specific Mortality of Differentiated Thyroid Cancer Patients in Korea: A Multicenter Cohort Study

• Jeon MJ
• Kim WG
• Kim TH
• Kim HK
• Kim BH
• Yi HS
• Kim ES
• Kim H
• Kim YN
• Kim EH
• Kim TY
• Kim SW
• Kang HC
• Chung JH
• Shong YK
• Kim WB
• on behalf of the Korean Thyroid Cancer Study Group

• KMID: 2406187
• DOI: http://doi.org/10.3803/EnM.2017.32.4.434

Abstract

BACKGROUND
Little is known regarding disease-specific mortality of differentiated thyroid cancer (DTC) patients and its risk factors in Korea.
METHODS
We retrospectively reviewed a large multi-center cohort of thyroid cancer from six Korean hospitals and included 8,058 DTC patients who underwent initial surgery between 1996 and 2005.
RESULTS
Mean age of patients at diagnosis was 46.2±12.3 years; 87% were females. Most patients had papillary thyroid cancer (PTC; 97%) and underwent total thyroidectomy (85%). Mean size of the primary tumor was 1.6±1.0 cm. Approximately 40% of patients had cervical lymph node (LN) metastases and 1.3% had synchronous distant metastases. During 11.3 years of follow-up, 150 disease-specific mortalities (1.9%) occurred; the 10-year disease-specific survival (DSS) rate was 98%. According to the year of diagnosis, the number of disease-specific mortality was not different. However, the rate of disease-specific mortality decreased during the study period (from 7.7% to 0.7%). Older age (≥45 years) at diagnosis, male, follicular thyroid cancer (FTC) versus PTC, larger tumor size (>2 cm), presence of extrathyroidal extension (ETE), lateral cervical LN metastasis, distant metastasis and tumor node metastasis (TNM) stage were independent risk factors of disease-specific mortality of DTC patients.
CONCLUSION
The rate of disease-specific mortality of Korean DTC patients was 1.9%; the 10-year DSS rate was 98% during 1996 to 2005. Older age at diagnosis, male, FTC, larger tumor size, presence of ETE, lateral cervical LN metastasis, distant metastasis, and TNM stages were significant risk factors of disease-specific mortality of Korean DTC patients.

Keyword

Mortality; Risk factors; Thyroid neoplasms

MeSH Terms

Cohort Studies*
Diagnosis
Female
Follow-Up Studies
Humans
Korea*
Lymph Nodes
Male
Mortality*
Neoplasm Metastasis
Retrospective Studies
Risk Factors
Thyroid Gland*
Thyroid Neoplasms*
Thyroidectomy

Figure

• 

  Fig. 1 Time trends of disease-specific mortality of differentiated thyroid cancer patients in Korea based upon the year of initial diagnosis. During a median of 11.3 years of follow-up, 150 disease-specific mortalities (1.9%) occurred. (A) Among 150 cases, 114 cases (76%) were papillary thyroid cancers (PTCs) and 36 cases (24%) were follicular thyroid cancers (FTCs). (B) The number of disease-specific mortality was steady and ranged from 10 to 21 cases. (C) The rate of disease-specific mortality decreased during the study period. The blank bar indicates small primary tumors (≤2 cm) and the black bar indicates large primary tumors (>2 cm).

• 

  Fig. 2 Disease-specific survival (DSS) curves of Korean differentiated thyroid cancer patients. (A) The 5-, 10-, and 20-year DSS rates were 99%, 98%, and 94%, respectively. (B) DSS was significantly different according to the 7th edition of the tumor node metastasis (TNM) staging system (P<0.001).

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