The analysis of the results of thyroid fine needle aspiration biopsies made between January 2004 and July 2010 (The relationship between Hashimoto's Thyroiditis and Papillary Thyroid Cancer)

Thyroid nodules are frequent in the adult population. They are clinically important because of the thyroid cancer risk. Papillary thyroid cancer (PTC) is the most common one in all thyroid cancers. Hashimoto thyroiditis (HT) is the most common autoimmune thyroid disease. The association between PTC and HT has been highly debated in the literature. However the relationship remains controversial. Our aim is to investigate the relationship between these two diseases when researching the pathological results of thyroid fine needle aspiration biopsies performed in our own center within a certain time interval.We retrospectively rewieved 7321 thyroid fine needle aspiration biopsy (TIIAB) results with their biochemical, radiological, scintigraphical records, seen in Dokuz Eylül University Hospital between January 2004 and July 2010. When recording the pathological results of these patients, who were perfomed TIIAB, with their demographical and clinical data, we also investigated the relationship between PTC and HT in these patients. All of the data were analyzed statistically using SPSS 17.0.Totally 7321 nodules were evaluated. Most of them (80.6%) were in female and benign cytology (82.3%). One thousand five hundred eighty seven patients were diagnosed HT. HT was more common in female patients 89% (p<0,001). Although the PTC was diagnosed 0.4% in the whole group of patients, PTC diagnosis was more common (8%) in patients with HT. Nine hundred seventy two patients underwent surgery. Most of them were female (81.9%). HT diagnosis was significantly more prevalant (48.2%) in patients with PTC when compared to patients with benign thyroid disorders diagnosed after surgery (24.8%) (p<0,001). Correlation analysis revealed that female sex, presence of HT, and TSH had positive, age and the size of nodule had negative correlations with the development of PTC. Multivariate regression analysis showed that young age, the presence of HT and the smaller nodule size were independent risk factors for development of PTC. Smaller nodule size, young age and the presence of HT were independently associated with PTC. The presence of HT was associated with increased risk of development of PTC (OR:3.47) (%95 CI: 2.73-4.40). Moreover HT was associated with multifocal / multicentric thyroid cancer develepment (p:0.02).Our study showed that HT was an independent risk factor for development of PTC. Moreover HT is also associated with multifocal / multicentric PTC. That?s why the HT patients particularly with nodular HT patients should be observed carefully and performed TIIAB when necessary.Key words: Thyroid nodule, Fine needle aspiration biopsy, Hashimoto?s thyroiditis, Papillary thyroid cancer