Predictive Factors of Athyroglobulinemia After Total Thyroidectomy for Papillary Thyroid Cancer

Background: Thyroglobulin (Tg) is the specific tumor marker for epithelial thyroid cancer. It holds significant value in the postoperative period, and somehow, the goal of surgery in papillary thyroid cancer (PTC) undergoing total thyroidectomy is to achieve undetectable levels of postoperative thyroglobulin (uTg). Methods: This is a retrospective single-center study in which first basal Tg values were evaluated post-surgery in PTC patients undergoing total thyroidectomy. Patients with elevated antithyroglobulin antibodies were excluded. The impact of various demographic, clinical, therapeutic, tumor-stage related, and histopathological variables on the achievement of undetectable thyroglobulin levels (uTg, <1 ng/mL) was studied. A descriptive and logistic regression-based bivariate and multivariate analysis was planned using STATA vs. 16.1. program. The significance level was stated at 0.05. Results: Basal athyroglobulinemia was obtained in 89.6% of 202 patients operated on between January 2015 and June 2023 in a single referral institution. Due to the limited number of cases with detectable Tg, multivariate analysis could not be performed. The main factors that favored its achievement on bivariate analysis were a smaller tumor size (p = 0.003), no need for extended resections due to local invasion beyond the thyroid gland (p = 0.003) or neck dissection (p = 0.039), absence of distant metastases (p = 0.000), and a lower MACIS score (p < 0.000). Conclusions: The achievement of uTg was closely related to factors related to tumor stage (tumor diameter, lymph node spread, and metastatic disease), and it was not influenced by differences in epidemiological data, clinic manifestations, preoperative diagnosis, multifocality, or the presence of aggressive cytological variants.