Abstract 5284: Recurrent Middle Eastern differentiated thyroid carcinoma has worse outcome than persistent disease

Abstract Background: Differentiated Thyroid Cancer (DTC) is the most common endocrine malignancy. Despite its excellent prognosis, recurrent and persistent disease remain major challenges after initial treatment. Although most studies have considered persistence and recurrent as a single entity, emerging studies to differentiate recurrent and persistent disease are controversial and study on recurrent and persistent DTC from Middle Eastern ethnicity is lacking. Methods: We retrospectively analyzed 1822 patients who underwent surgery ± I131 treatment for DTC with a median age of 38.9 years and median follow-up of 90 months. Results: We found a similar prevalence rate of persistent and recurrent disease (16.4% vs. 16.6%) in Middle Eastern DTC patients. Relative to patients with persistent disease, patients with recurrent disease were significantly older (median age 36.1 vs. 45.8 years; p < 0.0001), were more likely to have ATA high risk tumors (p < 0.0001) and had a higher rate of distant metastasis (p < 0.0001). However, structural disease had an almost similar frequency in both recurrent and persistent disease (72.2% vs 73.3%). On multivariant logistic regression analysis, both T status and N status are independent predictors for both recurrent and persistent disease. However, older age, extrathyroidal extension and the presence of distant metastasis were independent predictors of only recurrent disease. In addition, patients with recurrent disease had significantly worse overall survival (OS; p < 0.0001) and cancer specific survival (CSS; p < 0.0001), which remained significant in multivariate Cox proportional hazard model (Hazard ratio = 2.72; 95% confidence interval = 1.20 - 7.01; p = 0.0153 for OS and Hazard ratio = 5.09; 95% confidence interval = 2.10 - 15.24; p = 0.0001 for CSS). Conclusion: Although persistent and recurrent disease in Middle Eastern DTC have similar frequencies, recurrent disease had worse outcome compared to persistent disease. This has great potential clinical relevance to differentiate recurrene from persistence for therapeutic and follow-up approach for improving outcomes of DTC patients from Middle Eastern ethnicity. Citation Format: Sandeep K. Parvathareddy, Abdul K. Siraj, Padmanaban Annaiyappanaidu, Nabil Siraj, Saeeda O. Ahmed, Zeeshan Qadri, Saud Azam, Khawla S. Al-Kuraya. Recurrent Middle Eastern differentiated thyroid carcinoma has worse outcome than persistent disease. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5284.