Effect of Different Ablative Doses of Radioactive Iodine in Patients with Differentiated Thyroid Carcinoma and Cervical Lymph Node Metastasis

Background: Thyroid cancer is the most prevalent endocrine malignancy 
accounting for 2% of all cancers in Egypt. Differentiated thyroid cancer (DTC) 
is the most histopathological subtype. Surgery with postoperative radioactive 
iodine (RAI) ablation is the standard treatment. Cervical lymph node metastasis 
is most popular site of metastasis. 
Objective: The study aims to assess the effect of different doses of RAI 131I on 
progression free survival (PFS) and overall survival (OAS) in patients with DTC 
and cervical LN metastasis.
Patients and Methods: Seventy patients with DTC with cervical lymph node 
metastasis who had been seen at the Clinical Oncology Department, Mansoura 
University Hospitals between 1st of 2015 to the end of 2020 were included in 
this retrospective analysis.
Results: Male to female ratio was 1:1.8. The mean age was 40.98 (SD ± 14.34) 
years ranging from 18-69 years. Papillary thyroid carcinoma (PTC) represented 
62 patients (88.6%). Fifty-seven (81.4 %) of patient were presented with stage I 
disease. Mean OAS was 64.01 (SD ± 14.18) ranging from 15-92 months. The 2-
year PFS was 88.6% with mean PFS 46 (SD ±19.7). OAS prognostic factors 
were stage, tumor size (T-stage), presence of ECE or patient performance status 
(p-value = <0.001, 0.002, 0.041, and 0.024 respectively).
Conclusion: The high postoperative TG, PNI, ENE and higher number of 
involved LNs have negative clinical outcome. RAI ablation is essential for the 
right patient after confirming the risk category to improve the course of the 
disease, increase survival rates, and stop additional recurrences.