Influence of chronic lymphocytic thyroiditis on the risk of persistent and recurrent disease in patients with papillary thyroid carcinoma and elevated antithyroglobulin antibodies after initial therapy.

INTRODUCTION: In patients with papillary thyroid carcinoma who have negative serum thyroglobulin after initial therapy, the risk of structural disease is higher among those with elevated antithyroglobulin antibodies compared to patients without antithyroglobulin antibodies. Other studies suggest that the presence of chronic lymphocytic thyroiditis is associated with a lower risk of persistence/recurrence of papillary thyroid carcinoma. OBJECTIVE: This prospective study evaluated the influence of chronic lymphocytic thyroiditis on the risk of persistence and recurrence of papillary thyroid carcinoma in patients with negative thyroglobulin but elevated antithyroglobulin antibodies after initial therapy. METHODS: This was a prospective study. Patients with clinical examination showing no anomalies, basal Tg<1ng/mL, and elevated antithyroglobulin antibodies 8-12 months after ablation were selected. The patients were divided into two groups: Group A, with chronic lymphocytic thyroiditis on histology; Group B, without histological chronic lymphocytic thyroiditis. RESULTS: The time of follow-up ranged from 60 to 140 months. Persistent disease was detected in 3 patients of Group A (6.6%) and in 6 of Group B (8.8%) (p=1.0). During follow-up, recurrences were diagnosed in 2 patients of Group A (4.7%) and in 5 of Group B (8%) (p=0.7). Considering both persistent and recurrent disease, structural disease was detected in 5 patients of Group A (11.1%) and in 11 of Group B (16.1%) (p=0.58). There was no case of death related to the disease. CONCLUSION: Our results do not support the hypothesis that chronic lymphocytic thyroiditis is associated with a lower risk of persistent or recurrent disease, at least in patients with persistently elevated antithyroglobulin antibodies after initial therapy for papillary thyroid carcinoma.