Abstract
Objectives:
Evaluate whether the presence of preoperative thyroglobulin antibody (TgAb) levels can help predict the final pathology of thyroid nodules. Assess whether higher levels of preoperative TgAb increase the likelihood that a thyroid nodule is malignant.
Methods:
A retrospective chart review of patients who underwent thyroidectomy in 3 McGill University-affiliated hospitals between January 2012 and 2014 was conducted. Demographic data, TgAb levels, and final histopathology were recorded. Patients were divided into 2 groups: TgAb positive (defined as TgAb ≥30 IU/mL) and TgAb low/negative (defined as TgAb <30). Micropapillary thyroid carcinomas were considered to be benign. These data were then statistically analyzed using SPSS.
Results:
Preoperative TgAb levels were available in 412 patients. There were 360 patients in the TgAb low/negative group (malignancy rate: 51.39%) and 52 patients in the TgAb positive group (malignancy rate: 65.38%). The sensitivity, specificity, positive predictive value, and negative predictive value of TgAb ≥30 IU/mL as a diagnostic test for thyroid malignancy were 15.53% (confidence interval [CI] 11.00-21.01), 90.67% (CI 85.66-94.38), 65.38% (50.91-78.03), and 48.61% (CI 43.34-53.91), respectively. The relative risk was 1.2723 (CI 1.0192-1.5883) and the odds ratio was 1.7868 (CI 0.9732-3.2804). Both the Pearson chi-square test (P = .024) and Fisher’s exact test (P = .017) yielded statistical significance between the 2 groups.
Conclusions:
Our study demonstrates that patients with preoperative TgAb ≥30 IU/mL had a higher rate of malignancy when compared to patients with TgAb <30 IU/mL. This suggests that an elevated TgAb level may increase the risk that a thyroid nodule is malignant.