Are Serum Thyroglobulin Levels a Reliable Marker of Recurrence in Thyroid Cancer?
Posted: Monday, November 23, 2020
According to a case study published in Case Reports in Endocrinology, unstimulated serum thyroglobulin levels following therapy in patients with differentiated thyroid cancer may not be a reliable predictive factor for nodal recurrence. These patients may also include those treated with thyroidectomy as well as those who undergo radioiodine therapy.
“This may be particularly true in [differentiated thyroid cancer] patients with low presurgical serum [thyroglobulin] levels, in whom the tumor either produces little [thyroglobulin] or, alternatively, has lost the capacity to secrete [thyroglobulin],” concluded Arnoldo Piccardo, MD, of Galliera Hospital, Genoa, Italy, and colleagues.
The case study focused on a patient (aged 65) who initially presented with neck pain and a lump in the left side of his neck. Ultrasonography identified a multinodular goiter, including a high-risk hypoechoic nodule in the left thyroid. The patient had very low thyroglobulin serum levels (1.4 ng/mL). Due to the high malignancy risk of the nodule, PET and CT scans were performed, revealing an intense uptake, but fine-needle aspiration cytology results indicated the nodule was benign. Despite that classification, the suspicious clinical features of the nodule led to a total thyroidectomy being performed. Radioiodine therapy was also administered after histology identified a tall cell papillary thyroid carcinoma variant with scattered thyroglobulin expression. The patient received suppressive L-thyroxine therapy.
While undergoing L-thyroxine therapy, the patient experienced undetectable levels of serum thyroglobulin. However, left laterocervical lymph-node recurrence was noted twice within 6 years of thyroidectomy, with serum thyroglobulin levels indicative of metastasis occurring during the second recurrence alone. Surgery was performed on each recurrence. The immunohistochemical expression of thyroglobulin and cytokeratin 19 at recurrence was comparable to the expression at initial diagnosis, and histology confirmed the disease had metastasized to the lymph nodes.
Disclosure: The study authors reported no conflicts of interest.