Correlation Of Hypothyroidism With Survival In Metastatic Renal Cancer Patients Treated With Sorafenib Or Sunitinib

379 Background: To investigate prognostic markers in patients with metastatic renal cell carcinoma (mRCC) undergoing treatment with the tyrosine kinase inhibitors (TKIs) sorafenib (So) or sunitinib (Su). Methods: Eighty-three patients with mRCC, who were treated at our institution between 2006 and 2009, were evaluated prospectively. Clinical and laboratory parameters were investigated, as well as, treatment-related adverse events. Subclinical hypothyroidism was characterized by serum TSH above the upper limit of normal and both total triiodtyronine (T3) and thyroxine (T4) within normal limits. Clinical hypothyroidism was defined as low serum T3 and T4 together with elevated TSH. Results: Thirty-one (37.3%) patients received So, and 52 (62.7%) were treated with Su. In univariate analyses, a poor ECOG status was associated with an unfavorable progression-free survival (PFS) (p<0.0001); similarly high risk MSKCC criteria correlated with a worse PFS (p=0.003). Furthermore, response to therapy was a surrogate parameter (p<0.0001). Twenty-one of 66 (31.8%) patients developed hypothyroidism during treatment, which was associated with a positive prognosis (p=0.032). In multivariate analyses, only the ECOG status (ECOG 0/1 vs. ECOG 2, p=0.018) and hypothyroidism (p=0.01) were independent prognostic parameters. Conclusions: The development of hypothyroidism during treatment might be useful as a clinical predictor of PFS for mRCC patients undergoing treatment with targeted agents. No significant financial relationships to disclose.