Thyroglobulin antibodies as a potential predictive marker of papillary thyroid carcinoma in patients with indeterminate cytology.

BACKROUND

We investigated the efficacy of thyroglobulin antibodies (TgAb) in detecting malignancy in indeterminate thyroid nodules and evaluated the possible association between TgAb and autoimmunity in papillary thyroid carcinoma (PTC).

METHODS

This retrospective, nonrandomized study included 1,646 patients who had undergone preoperative fine-needle aspiration biopsy to evaluate their thyroid nodules, and then standard total thyroidectomy. Of 194 patients (11.8%) with indeterminate nodules, 61 (31.4%) had PTC and 133 (68.6%) had benign nodules at the final histologic examination.

RESULTS

Univariate analysis showed that multifocality (P = .002), bilaterality (P = .003), lymph-node metastasis (P = .030), and capsule penetration (P = .003) were significantly associated with positive TgAb in patients with indeterminate cytology and histopathologic diagnosis of PTC. The multivariate analysis showed that TgAb positivity (P < .001) and preoperative thyroid-stimulating hormone levels (P = .022) were independent predictive factor for PTC diagnosis in patients with indeterminate cytology.

CONCLUSIONS

Preoperative TgAb could be a marker for PTC in patients with indeterminate thyroid nodules, increasing diagnostic accuracy. TgAb positivity could also influence the clinical assessment and subsequent selection of total thyroidectomy.