The Effect of Histology, Gender and Stage on the Treatment of Thyroid Cancer

Introduction. Differentiated thyroid carcinoma makes up to 90% of all thyroid cancers. Literature review indicates that surgery is the primary mode of treatment for this type of thyroid carcinoma and is associated with lower recurrence rate. Objective. To investigate effect of surgery plus adjuvant therapy vs. surgery alone on the evidence or no evidence of thyroid cancer at the follow up. To investigate if the effect was confounded or modified by histological type, stage, or gender. Methods. Secondary database analysis of 4,699 patients diagnosed with thyroid carcinoma in Florida between January 1, 1994 and December 31, 2002 was performed. The Chi-square- General Association tested the independence of the treatment vs. outcome in the presence of the third stratification factor. Mantel-Haenszel stratified methodology was used to analyze all three third factors. Results. Patients with localized papillary thyroid carcinoma (PTC) are 20 % more likely to have evidence of carcinoma if they undergo surgery plus adjuvant therapy than patients with follicular variant of papillary thyroid carcinoma (FVPTC). Histology, gender and stage were found to be EM, risk factor and confounder, respectively. Conclusion. The data analysis suggests that patients with PTC, who were treated with surgery and adjuvant therapy, may more likely to have evidence of cancer at the follow up than patients with FVPTC. Authors suggest that histology, gender and stage should be considered and controlled for during planning stage of the study and/or during analysis.