Androgen receptor mRNA expression is a predictor for recurrence-free survival in non-muscle invasive bladder cancer

BACKGROUND: Non-muscular invasive bladder cancer (NMIBC) has a high risk of recurrence. As androgen receptor (AR) reportedly affects bladder cancer, we assessed the correlation between NMIBC recurrence and tumor AR expression in Japanese patients. METHODS: We retrospectively reviewed 53 specimens of non-metastatic NMIBC, with recurrence-free survival (RFS) as the primary endpoint. We used real-time quantitative polymerase chain reaction to quantify AR mRNA expression. Kaplan–Meier product-limit estimators were used to assess RFS distribution, log-rank tests to analyze differences in RFS between high- and low-risk groups; and multivariate analyses of AR mRNA expression and other clinicopathological factors to predict independent factors for RFS. RESULTS: The high AR mRNA-expressing group (n = 43) tended to have a longer median RFS (not reached) than did the low-AR group (n = 10; 9.04 months; P = 0.112). Multivariate analysis showed female sex (hazard ratio [HR]: 7.360, 95% CI: 1.649–32.856, P = 0.009), tumor size ≥3 cm (HR: 23.697, 95% CI: 4.383–128.117, P < 0.001) and low AR mRNA expression (HR: 0.202, 95% CI: 0.048–0.841, P = 0.028) to be independent predictors of shorter RFS. CONCLUSION: Our study showed that low AR mRNA expression level is an independent risk factor for RFS in Japanese patients with NMIBC. Further studies are necessary but AR expression might be a new indicator of recurrence of NMIBC.