Thyroglobulin determination, neck ultrasonography and iodine-131 whole-body scintigraphy in differentiated thyroid carcinoma

The long-term prognosis of patients with differentiated thyroid carcinoma depends on the early diagnosis and treatment of metastases and local recurrences. We evaluated serum thyroglobulin measurements, neck ultrasonography with ultrasound-guided biopsy and I-131 whole-body scintigraphy in the follow-up of 359 patients after surgical thyroidectomy and radioiodine ablation of the thyroid remnant, Methods: Serum thyroglobulin levels were determined and considered abnormal when the values were >5 ng/ml, Ultrasonography over the entire neck region and fine-needle aspiration biopsy of the mass or enlarged lymph nodes were carried out using 5- and 7,5-MHz transducers and 23-gauge needles, Whole-body scintigraphy was performed after administration of 185 MBq (5 mCi) I-131. Results: Increased levels of thyroglobulin (ranging from 12 to >600 ng/ml) were measured in 40 of 55 (73%) patients with metastases or local recurrences, Ultrasonography revealed occult neck masses that were not detected by other methods, Neck ultrasonography and ultrasound-guided biopsy were positive for malignancy in 23 patients. Thyroglobulin levels were undetectable in 12 (52%) of these patients and I-131 whole-body scintigraphy was negative in 19 (83%) of them, Conclusion: The combined use of three diagnostic modalities (measurement of serum thyroglobulin, neck ultrasonography with ultrasound-guided biopsy for detecting recurrences of carcinoma in the neck region and I-131 whole-body scintigraphy) appears to give the best results in the follows-up patients with differentiated thyroid carcinoma.