Risk Factors Associated With Reoperative Surgery for Thyroid Malignancies: A Retrospective Cohort Study

Objective To examine various factors associated with an increased risk of reoperation for persistent or recurrent malignant thyroid cancers. Study Design Retrospective cohort study. Setting Tertiary academic hospital centers. Methods Patients undergoing surgery for thyroid cancer at 2 tertiary academic institutions from 2006 to 2020 were included. Those who underwent a reoperative procedure were compared with patients only requiring 1 procedure. The Pearson chi-square and independent t test were used to compare group data accordingly. Furthermore, a binomial logistic regression was performed, while machine learning models were used to construct a predictive algorithm. Results This study included 2266 patients with surgically managed thyroid malignancy, of which 54 (2.4%) necessitated reoperations. Those requiring a second surgical procedure were more likely to be male (40.7% vs 20.9%, P < .001), undergo bilateral (24.1% vs 3.3%, P < .001) and lateral (16.7% vs 1.8%, P < .001) neck dissections, and have a greater number of metastatic lymph nodes (mean, 9.1 vs 3.5; P < .001) and a larger tumor size (mean, 3.0 vs 2.0 cm; P < .001). According to the binomial logistic regression model, lateral neck dissection, greater number of metastatic lymph nodes, and larger tumor size significantly increased the odds of necessitating a second procedure by 7.8 (95% CI, 2.523-24.083), 1.1 (95% CI, 1.032-1.152), and 1.3 (95% CI, 1.064-1.559), respectively. Last, machine learning models could not significantly predict the occurrence of reoperation. Conclusion This study identified patient- and cancer-related characteristics associated with an increased risk of requiring reoperation for thyroid malignancies.