Abstract 730: Annual hazard rate of recurrence in Middle-Eastern papillary thyroid cancer over a long-term follow-up

Abstract

Predicting the pattern of recurrence is necessary to establish optimal surveillance and treatment strategies. We identified patient population that remain at risk for an event and clarify changes in the hazard rate (HR) for tumor recurrence overtime in Middle Eastern patients with Papillary Thyroid Cancer (PTC). Data for 1201 PTC patients from single institute with median follow-up of 9.5 years were analyzed. Estimated HR were plotted overtime for the entire cohort, as well as for radioactive iodine (RAI) ablation in patients separately. The changes in risk were further analyzed according to clinical variable and factors predictive of early (≤ 5years) and late (>5 years) recurrence were explored using Cox regression analysis. Tumor recurrence was noted in 18.4% (221/1201) patients. The annualized hazard of PTC recurrence was highest during the first 5 years (2.8%), peaking between 1 - 2 years (3.7%), with a second smaller peak between 13 - 14 years (3.2%). Patients receiving RAI therapy had a lower hazard of recurrence compared to those who did not receive RAI therapy (1.5% vs 2.7%, p = 0.0001). Importantly, this difference was significant even in the intermediate-risk PTC patients (0.7% vs 2.3%; p = 0.0001). Interestingly, PTC patients who were male, aged ≥ 55 years, with lymph node involvement and advanced stage disease were still at high risk for late recurrence. In conclusion, we confirmed the validity of double-peaked time-varying pattern for risk of recurrence in Middle-Eastern PTC patients. Furthermore, according to the time distribution of recurrence hazard, we could formulate individualized treatment and surveillance plans in PTC patients. Citation Format: Abdul K. Siraj, Sandeep K. Parvathareddy, Zeeshan Qadri, Saud Azam, Felisa De Vera, Maha Al-Rasheed, Wael Haqawi, Hassan AlDossari, Khawla S. Al-Kuraya. Annual hazard rate of recurrence in Middle-Eastern papillary thyroid cancer over a long-term follow-up [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 730.