Abstract 6278: Effect of tumor size and BRAF mutational status in Middle Eastern differentiated thyroid cancer

Abstract

Abstract Background: Risk stratified treatment strategies have become a focus in the treatment of Differentiated Thyroid Cancer (DTC). Tumor size at diagnosis has been widely used as a major mortality risk factor in risk stratification of DTC, but whether this is generally applicable, particularly in patient with different BRAF genetic backgrounds, is unclear. The current study was designed to analyze whether tumor size at diagnosis is a major prognostic factor in Middle Eastern DTC. Methods: We conducted a comparative study of the relationship between tumor size at diagnosis and event free survival with respect to BRAF status in 1709 consecutive patients treated surgically for Middle Eastern DTC. Patients were divided into four groups according to the size of tumor (≤4 cm vs. >4 cm) and BRAF mutation status: Group 1 (≤4 cm without BRAF mutation, n = 587), Group 2 (≤4 cm with BRAF mutation, n = 765), Group 3 (>4 cm without BRAF mutation, n = 198) and Group 4 (>4 cm with BRAF mutation, n = 159). Predictors of event-free survival (EFS) were compared using the Log-rank test and Cox proportional hazards models. Results: Following multivariate analysis, patients with tumors >4cm did worse than patients with tumors <4cm with respect to EFS (Group 3 vs Group1 HRadjusted=1.38, 95% CI=1.02-1.86, p = 0.0359; Group 4 vs Group 2 HRadjusted=1.61, 95% CI=1.20-2.16, p = 0.0017). However, patients did not differ according to EFS, regardless of the presence of BRAF mutation within each size category (Group 2 vs Group 1 HRadjusted=0.98 CI=.78-1.23, p=0.8415 ; Group 4 vs Group 3 HRadjusted=1.17, 95% CI=0.84-1.62, p=0.3523] Conclusion: Tumor size is an independent predictor of EFS in Middle Eastern DTC patients, regardless of BRAF mutational status. Citation Format: Rong Bu, Abdul K. Siraj, Sandeep K. Parvathareddy, Kaleem Iqbal, Saud Azam, Zeeshan Qadri, Maha Al-Rasheed, Wael Haqawi, Allianah D. Benito, Khawla S. Al-Kuraya. Effect of tumor size and BRAF mutational status in Middle Eastern differentiated thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6278.