Objectives: The incidence of flutamide-induced liver toxicity was studied in 30 consecutive patients with prostate cancer who were treated with total androgen blockage (TAB) therapy (luteinizing hormone releasing hormone [LHRH] analogue and flutamide) in our hospital during the last 3 years and in 20 consecutive patients with prostate cancer who were treated by partial androgen blockage (PAB) therapy (LHRH analogue alone).
Methods: Liver function test, including measurement of serum levels of aspartate aminotransferase (AST) alanine aminotransferase (ALT), total cholesterol, total bilirubin, gamma-glutamyl transpeptidase (gamma-GTP), and cholinesterase were performed at regular interval.
Results: The incidence of liver toxicity in patients receiving TAB (10 cases of 25 patients) was significantly higher than in patients receiving PAB (2 of 18 patients). Two patients in whom severe liver toxicity developed after receiving TAB were hospitalized. However, after flutamide was discontinued all patients with liver damage recovered with normalization of AST and ALT levels. Levels of total cholesterol and gamma-GTP did not differ significantly in either patient group. In two patients receiving TAB total bilirubin levels showed slight, transient elevations after maximum elevations of AST and ALT. In 80% of patients receiving TAB serum levels of cholinesterase were significantly higher than those in patients receiving PAB.
Conclusion: These data suggest that the risk of flutamide-induced liver toxicity is significant in patients receiving TAB. However, this damage can be normalized after flutamide has been discontinued. Serum levels of cholinesterase also increase significantly in patients receiving TAB. This previously unreported phenomenon suggests an unknown effect of flutamide on liver function in patients with prostate cancer.