Clinical Significance Of Co-Existance Of Hashimoto Thyroiditis (HT) With Differentiated Thyroid Cancer (DTC)

Abstract Background Hashimoto's Thyroiditis represents a long-term autoimmune condition which ordinarily develops in people diagnosed with Differentiated Thyroid Cancer. The connection between these disorders and how Hashimoto’s Thyroiditis affects thyroid malignancy development remains unknown. The current research examined how Hashimoto’s Thyroiditis affects tumor aggressiveness in Diffused Thyroid Cancer patients by analyzing tumor size rates and lymph node metastasis and pathological invasiveness outcomes. Methods The study examined 198 patients who underwent thyroidectomy between June 2023 and March 2025 through an observational retrospective review. The research included two discrete patient groups with and without Hashimoto’s Thyroiditis. Tumor size measurements together with nodal status reports and capsular invasion status received analysis from both groups of patients. The study used descriptive statistics together with Mann–Whitney U test along with Chi-square test to determine differences between groups. The authors built a multivariate logistic regression framework to confirm whether Hashimoto’s Thyroiditis functioned as an individual determinant of tumor aggressive behavior. Performance prediction was evaluated with receiver operating characteristic curve analysis while a nomogram functioned to create personalized risk estimates. Results Patients with Hashimoto’s Thyroiditis had significantly smaller tumors (median size: 9 mm vs. 12 mm, p = 0.003) and a lower frequency of lymph node metastasis (25.0% vs. 38.0%, p = 0.043) compared to those without thyroiditis. Multivariate analysis confirmed that Hashimoto’s Thyroiditis was associated with reduced odds of tumor aggressiveness (odds ratio = 0.68, 95% CI: 0.47–0.98, p = 0.041), independent of tumor size and nodal involvement. While the logistic model demonstrated modest discriminative ability (AUC = 0.587), calibration performance was strong (mean absolute error = 0.025). The nomogram provided an interpretable tool for individualized prediction. Conclusions The presence of Hashimoto’s Thyroiditis in patients with Differentiated Thyroid Cancer is associated with less aggressive tumor features. These findings suggest a potentially protective role of autoimmune thyroiditis and support its consideration in risk stratification and clinical management decisions. Further prospective studies are warranted to validate these observations and explore underlying immunological mechanisms.