Is there a correlation between thyroiditis and cancer?

Background In the past few decades, the incidence of thyroid cancer has increased significantly all over the world. In the same period, there also seems to have been an increase in the incidence of Hashimoto's Thyroiditis-the most common inflammatory autoimmune thyroid disease. Several studies have linked thyroiditis to thyroid cancer. Methods In our study, we examined 2304 cases of thyroid surgery collected over a 12-year period starting from 2004. In 2090 cases (90.7%) out of our sample, it has been possible to compare the presence, or lack thereof, of thyroiditis by means of a histological diagnosis post-surgery; 214 (9.3%) cases were excluded from our study due to insufficient data. We then divided the different histological classifications into two groups. Group A included all the benign histological classifications and Group B included all the malignant histological classifications. In each group, we then assessed the presence, or lack thereof, of thyroiditis in order to evaluate if thyroiditis can be linked to a higher incidence of thyroid cancer. Results Data analysis showed a higher incidence of thyroiditis in Group B, 36.4% (malignant pathology report), than in Group A, 32.4% (benign pathology report), but no statistically significant difference emerged between those two groups (P > 0.05). Conclusions Our conclusion was that a correlation between thyroiditis and a higher incidence of thyroid cancer is still undefined.