Is There Any Association Between Thyroid Cancer and Hashimotos Thyroiditis?

Thyroid cancer (TC) is the most common endocrine malignancy. The association between inflammation and cancer is well established but the association between thyroiditis (inflammation of thyroid gland) especially Hashimoto's thyroiditis (HT) and thyroid cancer remains controversial. Chronic inflammation leads to a repeated cycle of cellular damage and subsequent healing which contributes to inappropriate cell proliferation and subsequent neoplastic transformation. One of the most common forms of Thyroiditis is Hashimoto's thyroiditis which is a chronic autoimmune inflammatory disease affects almost 5% of the population and is more common in women. For the first time, Dailey and Lindsay reported in 1955 an increased association between Hashimoto's Thyroiditis (HT) and thyroid cancer. They reported 35 thyroid cancers in 278 patients with Hashimoto's Thyroiditis, a prevalence of 17.7% which they considered higher than the general population . Since then, various studies have been done, some studies have reported an increased risk of malignancy in Hashimoto's thyroiditis; others have failed to find an association. Most of the studies that have been done to identify the association between Hashimoto's thyroiditis and thyroid cancer are retrospective. The purpose of this pilot case-control study is to identify the association of Hashimoto's thyroiditis and thyroid cancer, to determine if the presence of Hashimoto's thyroiditis has any affect on the complication of thyroidectomy and prognostic factors of thyroid cancer.