Pre-operative serum TSH levels: A risk factor for advanced metastatic differentiated thyroid carcinoma

Background and Objective: As the thyroid cancer incidence is increasing, the search for its risk factor is becoming more important. Serum thyroid stimulating hormone (TSH) levels being a growth factor for normal thyroid tissue, is also considered as growth promotor of cancer cells. In our study we aimed for pre-operative serum TSH levels of Differentiated thyroid cancers (DTC) done before their first surgery and determined its association with advanced disease in terms of stage, multifocal disease, lymph node involvement and distant metastasis. Methods: We have conducted a retrospective review of thyroid cancers from 1st January 2008 to 31st December 2017. Out of 281, 142 cases were included according to inclusion criteria. We noted the demographic details of participants, their histopathological diagnosis and serum TSH levels done before first surgery from the medical records. We calculated the stage of tumor through modified American Joint Committee (AJCC) staging system. Results: Out of 147 participants, 89.4% had papillary carcinoma or its variants whereas 10.6% reported follicular carcinoma. The mean pre-op TSH level of the patients included was 2.04 ± 1.79. In addition to the descriptive analysis, the univariate regression analysis revealed that the association of serum TSH levels was found to be statistically insignificant with advanced stage of thyroid cancer, multifocal disease, lymph node metastasis and distant metastasis respectively. Conclusion: The serum TSH levels before surgery was not associated with poor prognosis of differentiated thyroid cancer with respect to higher staging, multifocal disease, lymphatic or distant metastasis.