Background: Most investigations of thyroidectomy for metastatic renal cell carcinoma (RCC) are case studies or small series. This study was conducted to determine the contribution of clinical and histopathologic variables to local recurrence in the neck and overall survival after thyroidectomy for RCC metastases.
Methods: The medical records of 140 patients with thyroidectomy for metastatic RCC performed between 1979 and 2012 at 25 institutions in Germany and Austria were analyzed.
Results: The median interval between nephrectomy and thyroidectomy was 120 months. Concurrence of thyroid and pancreatic metastases was present in 23 % of the patients and concurrence of thyroid and adrenal metastases in 13 % of the patients. Clinical outcome data were available for 130 patients with a median follow-up period of 34 months. The 5-year overall survival rate was 46 %, and 28 % of patients developed a local neck recurrence at a median of 12 months after thyroidectomy. Multivariate analysis showed that invasion of adjacent cervical structures (hazard ratio [HR] 3.2; p = 0.001), patient age exceeding 70 years (HR 2.5; p = 0.004), and current or past evidence of metastases to nonendocrine organs (HR 2.4; p = 0.003) were independent determinants of inferior overall survival. Conversely, invasion of adjacent cervical structures (HR 12.1; p < 0.0001) and year of thyroidectomy (HR 5.7 before 2000; p < 0.0001) were shown to be independently associated with local recurrence in the neck by multivariate analysis.
Conclusions: Although significant improvement of local disease control in patients with thyroid metastases of RCC has been achieved during the last decade, overall outcome continues to be poor for patients with locally invasive thyroid metastases.