Systemic inflammatory and thyroid markers for predicting malignancy in indeterminate (Bethesda III-IV) thyroid...

Numerous blood-based markers have been proposed as potential predictors of malignancy, not only in thyroid but also in various cancer types. This study aimed to evaluate the diagnostic utility of these markers for predicting malignancy in indeterminate thyroid nodules.

After literature review, we identified a set of markers potentially useful for predicting malignancy. Age, gender, nodule size, platelet count, mean platelet volume, platelet distribution width, lymphocyte/monocyte ratio, neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, platelet large cell ratio, immature granulocyte, thyroid-stimulating hormone, thyroglobulin, thyroglobulin-antibody and thyroid peroxidase-antibody levels were prospectively collected from patients who underwent thyroidectomy at our institution. The relationship between these markers and malignancy in indeterminate nodules was evaluated.

Among 1392 patients who underwent thyroidectomy between March-2021 and June-2024, 225 were operated for indeterminate thyroid nodules. In these patients, both nodule size ≥4 cm and serum thyroglobulin levels were found to be significantly associated with malignancy in univariate analysis (p < 0.05). ROC curve analysis identified a Tg cut-off value of 299 ng/mL. In multivariate analysis, when a nodule size threshold of 4 cm and a Tg cut-off of 299 ng/mL were applied, the significance of Tg as an independent predictor of malignancy became more pronounced.

The relationship between nodule size and malignancy is known, but elevated thyroglobulin levels have been found to be an independent risk factor for malignancy in indeterminate nodules. Although it needs to be generalized with more data, it is an inexpensive and simple diagnostic test that could guide us in patients with indeterminate cytologic findings.