[Incidental differentiated thyroid carcinoma is less prevalent in Graves' disease than in multinodular goiter].
OBJECTIVE
Risk factors for differentiated thyroid carcinoma (DTC) are poorly understood, but serum TSH levels, thyroid nodularity, and presence of autoimmunity are well-recognized factors that modulate DTC prevalence. TSH stimulates proliferation of both normal and neoplastic follicular cells. Consequently, thyroid-stimulating immunoglobulins (TSI), because of its TSH-like action, should induce DTC progression in patients with Graves' disease (GD). The study objective was to compare the prevalence of incidental DTC in patients undergoing thyroidectomy for benign thyroid disease.


METHODS
The pathology reports of 372 patients with preoperative diagnosis of euthyroid multinodular goiter (EMG) or hyperthyroidism were reviewed. Scintigraphy results and serum TSI levels were used to diagnosed either GD or hyperactive MG (HMG) to hyperthyroid subjects. Prevalence of DTC in each category was calculated using a Chi-square test.


RESULTS
EMG, GD, and HMG were diagnosed in 221, 125, and 26 patients. There were 58 DTCs, distributed as follows [n (%)]: EMG, 49 (22.2%); GD, 8 (6.4%), and HMG, 1 (3.8%). Difference in prevalence of incidental DTC between the groups was statistically significant (p<0.001). After adjustment for age, patients with EMG had a greater DTC prevalence than GD patients, with an OR of 4.17 (p<0.001). Tumor size (mm, mean ± SD) was 6.92 ± 11.26, 1.97 ± 1.85, and 9.0 for EMG, GD and HMG respectively (p=0.017).


CONCLUSIONS
Incidental DTC was less prevalent in GD as compared to EMG irrespective of age. This finding may suggest a predisposition to develop DTC in patients with thyroid nodular disease and/or a potential effect of autoimmunity to protect against development of neoplastic disease.
Departamento de Endocrinología y Nutrición, Clínica Universidad de Navarra, Universidad de Navarra, Pamplona, España.
Eider
E
Pascual Corrales
Rosa Maria
RM
Príncipe
Sara
S
Laguna Muro
Fernando
F
Martínez Regueira
Juan Manuel
JM
Alcalde Navarrete
Francisco
F
Guillén Grima
Juan Carlos
JC
Galofré
D018263:Adenocarcinoma, Follicular / Q000453:epidemiology*; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002291:Carcinoma, Papillary / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D006044:Goiter, Nodular / Q000097:blood / Q000150:complications / Q000453:epidemiology* / Q000601:surgery; D006111:Graves Disease / Q000097:blood / Q000453:epidemiology* / Q000276:immunology / Q000601:surgery; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000453:epidemiology / Q000209:etiology / Q000601:surgery; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D013963:Thyroid Hormones / Q000097:blood; D013964:Thyroid Neoplasms / Q000453:epidemiology*; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood
D018828:Immunoglobulins, Thyroid-Stimulating; D013963:Thyroid Hormones; D013972:Thyrotropin