ABSTRACT
Objective To study the antitumor mechanisms of pirarubicin (THP) and its effect on preventing postoperative recurrence of superficial bladder cancer. Methods MTT assay, flow cytometry and transmission electron microscope were used to assess the effects of different concentration of THP on T24 cell line. THP 40 mg in 50 ml distil water was used intravesically in 60 patients with transitional cell carcinoma after TURBT to prevent tumor recurrence. Results T24 cells were suppressed significantly by THP in concentrations of 10 mg/L and 100 mg/L,the suppressive rates being 80% and 94% respectively. Apoptosis peak was evident before G1 phase. The characteristics of cell apoptosis, such as bubble formation in cytoplasm and condensed chromosome, were typically manifested. Cells became necrotic when the concentration of THP was 1 000 mg/L. One course of THP intravesical administration was completed in 58 cases. All patients were followed up for a mean of 18.8 months (range 6～24 months), and tumor recurred only in 5 cases (8.6%). Conclusions Suppression of tumor cell growth and inducing apoptosis, even necrosis, might be the main antitumor mechanisms of THP. Clinically, intravesical administration of THP after TURBT was effective and safe for preventing tumor recurrence.