Higher serum thyroid stimulating hormone level in thyroid nodule patients is associated with greater risks of differentiated thyroid cancer and advanced tumor stage.
BACKGROUND
TSH is a known thyroid growth factor, but the pathogenic role of TSH in thyroid oncogenesis is unclear.


OBJECTIVE
The aim was to examine the relationship between preoperative TSH and differentiated thyroid cancer (DTC).


METHODS
The design was a retrospective cohort.


METHODS
Between May 1994 and January 2007, 1198 patients underwent thyroid surgery at a single hospital. Data from the 843 patients with preoperative serum TSH concentration were recorded.


METHODS
Serum TSH concentration was measured with a sensitive assay. Diagnoses of DTC vs. benign thyroid disease were based on surgical pathology reports.


RESULTS
Twenty-nine percent of patients (241 of 843) had DTC on final pathology. On both univariate and multivariable analyses, risk of malignancy correlated with higher TSH level (P=0.007). The likelihood of malignancy was 16% (nine of 55) when TSH was less than 0.06 mIU/liter vs. 52% (15 of 29) when 5.00 mIU/liter or greater (P=0.001). When TSH was between 0.40 and 1.39 mIU/liter, the likelihood of malignancy was 25% (85 of 347) vs. 35% (109 of 308) when TSH was between 1.40 and 4.99 mIU/liter (P=0.002). The mean TSH was 4.9+/-1.5 mIU/liter in patients with stage III/IV disease vs. 2.1+/-0.2 mIU/liter in patients with stage I/II disease (P=0.002).


CONCLUSIONS
The likelihood of thyroid cancer increases with higher serum TSH concentration. Even within normal TSH ranges, a TSH level above the population mean is associated with significantly greater likelihood of thyroid cancer than a TSH below the mean. Shown for the first time, higher TSH level is associated with advanced stage DTC.
Haymart
Megan Rist
MR
Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin, Madison, Wisconsin 53792, USA.
Repplinger
Daniel John
DJ
Leverson
Glen E
GE
Elson
Diane F
DF
Sippel
Rebecca S
RS
Jaume
Juan Carlos
JC
Chen
Herbert
H
D000328:Adult; D001707:Biopsy, Needle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D011989:Receptors, Thyrotropin / Q000235:genetics; D012189:Retrospective Studies; D012306:Risk; D013964:Thyroid Neoplasms / Q000209:etiology*; D016606:Thyroid Nodule / Q000097:blood* / Q000150:complications / Q000473:pathology; D013972:Thyrotropin / Q000097:blood*
D011989:Receptors, Thyrotropin; D013972:Thyrotropin