[Assessment of 8-hydroxy-2'-deoxyguanosine concentrations in bladder cancer patients treated with intravesical BCG instillation].

UNLABELLED: Increased 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentration has been proposed as reliable marker of the oxidative DNA damage, and prognostication of urological carcinogenesis, particularly in bladder cancer. Widely accepted method of treatment in early stages of bladder cancer is transurethral electro resection (TURN). Intravesical bacillus Calmette-Guerin instillation is considered to be the therapeutic agent for superficial transitional cell carcinoma (TCC) of the bladder and has been established as standard therapy in the patients. The aim of the study was to test the concentration of 8-OHdG in urine in patients with bladder cancer and the effect of TURN and BCG therapy on the 8-OHdG value.

MATERIAL AND METHODS: We tested 12 patients (3 female and 9 male) with superficial bladder cancer and 31 healthy controls. Urine for the examination was drawn in 4 time points: before and 2 weeks after TURN treatment, then 6 weeks after 6 intravesical instillations of BCG (Onko BCG--BIO MED Lublin) by Morales and 12 weeks after TURN. 8-OHdG concentration in urine was tested using ELISA commercial kit (OXIS health) and the values of 8-OHdG are expressed as ng/ml of urine.

RESULTS: Patients with superficial bladder cancer had 16.89 ng/ml of 8-OHdG in urine before the TURN procedure. The value was significantly (p< 0.005) higher then 12.98 ng/ml noted in healthy controls. 2 weeks after the procedure the 8-OHdG level decreased to 13.36 ng/ml. After 6 weeks of repeated 6 intravesical instillations of the BCG the concentration of 8-OHdG dropped to 10.91 ng/ml (p<0.005) and returned to the value 13.28 ng/ml after the next 4 weeks.

CONCLUSIONS: Patients with bladder cancer have significantly increased concentration of 8-OHdG in urine compared to controls. 8 week combine therapy with TURN and BCG resulted in a significant decrease in 8-OHdG concentration in urine The beneficial effect of BCG instillations seems to result from strengthening of the antioxidative DNA protection.