Bilaterality in papillary thyroid carcinoma: long-term outcomes and predictive factors

Bilaterality in papillary thyroid carcinoma (PTC) is a critical factor influencing surgical approach selection. This study aimed to investigate the long-term outcomes and predictive factors associated with bilaterality in PTC. This retrospective study reviewed 2,816 consecutive PTC patients who underwent total thyroidectomy between January 2013 and December 2015. Risk factors for bilaterality were analyzed using multivariate logistic regression. Among these, 1282 patients with ≥ 24-months follow-up were included in further recurrence/persistence analysis. The primary outcome measured was recurrence-free survival (RFS). Bilaterality was significantly associated with shorter RFS compared to unilateral PTC (p < 0.01), with a mean follow-up of 74.3 ± 33.3 months (median: 71 months; range: 24–140 months). Additionally, multifocality (OR = 4.58, p < 0.01), advanced N stage (N1a: OR = 1.36, p = 0.002; N1b: OR = 1.61, p < 0.01), obesity (OR = 1.74, p < 0.01), and a family history of thyroid cancer (OR = 2.16, p < 0.01) were independent predictors of bilaterality. A comprehensive preoperative examination should be conducted to detect bilaterality, particularly in PTC patients with identified risk factors. Additionally, intensive postoperative follow-up is recommended for patients with bilaterality to monitor for recurrence/persistence.