Thyroid metastases of renal cell carcinoma: clinical course in 45 patients undergoing surgery. Assessment of factors affecting patients' survival.

BACKGROUND Metastases of renal cell carcinoma (RCC) to the thyroid gland are uncommon. There is no clear consensus regarding the role of surgery in metastatic disease to the thyroid since most clinical studies include small numbers of patients. Also, risk factors associated with disease progression following thyroidectomy are not yet defined. We examined the determinants of the outcome in patients undergoing surgery for thyroid metastases of RCC. METHODS The medical records of 45 patients undergoing resection of thyroid metastases of RCC at 15 institutions in Germany and Austria were reviewed retrospectively. The outcome parameters assessed were overall survival and tumor-related survival. Factors associated with disease progression following thyroid surgery have been calculated. RESULTS The overall 5-year survival rate following thyroid metastasectomy was 51%. Nineteen patients died during the study: 14 of disseminated disease and 5 of non-tumor-related causes. In the multivariate analysis, the prognosis was significantly worse in patients older than > or = 70 years and in patients who had undergone nephrectomy for metastases in the contralateral kidney during the course of the disease. Nine patients developed a thyroid recurrence following surgery. No local disease relapse occurred if resection margins were documented to be free of the tumor. Of the 45 patients with thyroid metastases, 14 (31%) developed pancreatic metastases during the course of disease. Ten of these patients also underwent pancreatic surgery with a 5-year survival rate of 43% in this subgroup. CONCLUSIONS The overall survival of patients undergoing thyroidectomy for metastases of RCC is affected rather by general health status than by tumor-related factors. There is a significant coincidence of thyroid and pancreatic metastases of RCC.