Chronic Tyrosine Kinase Inhibitor (TKI) use in metastatic Renal Cell Carcinoma (mRCC): can this lead to the adverse effect of hypogonadism?

Background: Patients with metastatic renal cell carcinoma (mRCC) are commonly treated with tyrosine kinase inhibitors (TKIs). An adverse effect frequently suffered by patients is lethargy, which often leads to dose reduction or drug cessation. We aimed to assess whether hypogonadism is related to treatment with TKIs. Methods: We prospectively assessed gonadal function in 41 consecutive males with mRCC treated with TKIs. Demographic, clinical, and biochemical variables were collected, and statistical analyses performed to assess correlation and survival. Data Capture for each patient was perfomred at the time of entry in the study. Results: There was a 77% incidence of hypogonadism in this cohort. Assessment of testosterone level and time on TKI treatment revealed a correlation with linear regression R-2 of 0.24 and regression coefficient of -0.003 (p = 0.019). Odds ratio for hypogonadism at >30 months on TKIs was 12.1 (p = 0.011). Odds ratios above and below this value showed a confirmatory trend, suggesting that this may be a chronic adverse effect. Conclusions: Our findings provide an important and robust hypothesis for a prospective clinical trial to be performed. Expert Opinion: Given the present data, patients who have symptoms suggestive of hypogonadism must have an assessment of gonadal function and be treated.