The role of thyroidectomy in metastatic disease to the thyroid gland

Whether thyroidectomy for metastases to the thyroid is associated with a survival benefit remains debatable; in general, palliation and disease control are accepted goals in this setting. We evaluated the clinical features and overall survival of patients with thyroid metastasis treated by thyroid resection or nonoperatively.

This retrospective analysis included 90 patients identified with metastasis to the thyroid confirmed pathologically via thyroidectomy (n = 31) or fine-needle aspiration biopsy (n = 59). Overall survival was calculated by the Kaplan-Meier method, and differences between groups were calculated by Pearson's χ (2) coefficient.

The most common primary malignancies were renal cell (20%), head and neck (19%), and lung (18%). The median time from primary tumor diagnosis to thyroid metastasis diagnosis was 37.4 months (range 0-210 months). Most metastases (69%) were metachronous, and 12% were isolated. The median follow-up after diagnosis of thyroid metastasis was 11.5 months (range 0-112 months). Median overall survival was longer in thyroidectomy patients compared to the fine-needle aspiration group (34 vs. 11 months, P < 0.0001). Patients with renal cell primary tumors were more likely to undergo thyroidectomy than patients with other primary tumors (78 vs. 24%, P < 0.0001). Nearly all patients with lung primary tumors died within 24 months of thyroid metastasis diagnosis, and thyroidectomy was only offered to three patients.

Thyroidectomy was safe for selected patients with metastatic disease to the thyroid. Patients with metachronous or renal cell metastasis to the thyroid and whose primary tumor is/was treatable may be appropriate candidates for resection. Lung cancer metastasis to the thyroid is generally an ominous sign.