Cytological changes induced by intravesical bacillus Calmette-Guérin therapy for superficial bladder cancer

To evaluate cytological changes of urothelial cells with intravesical instillation therapy of the bacillus Calmette-Guérin (BCG), cytological specimens of voided urine from patients with superficial bladder cancer (pTa and pT1) treated with intravesical BCG therapy were examined. The following three groups of patients who had no evidence of recurrence more than 2 years after the treatment were studied: groups 1 and 2, patients who were treated with BCG (n = 22) and epirubicin, a derivative of doxorubicin (n = 22), respectively, for prophylaxis of intravesical recurrence after transurethral resection (TUR); and group 3, patients receiving no intravesical therapy after TUR (n = 12). Sixteen cytological characteristics were studied before and after the treatment in each group. In group 1 patients translucent nuclei and prominent nucleoli, vacuolization of cytoplasm, and eosinophilic cytoplasmic inclusions were frequently observed in urothelial cells as well as an increase in granulocytes, especially within 3 months after BCG instillation therapy. In group 2 patients an increased nuclear/cytoplasmic ratio, hyperchromatic nuclei and prominent nucleoli of urothelial cells were transiently found within 1-2 months after intravesical epirubicin therapy. In group 3, translucent nuclei and prominent nucleoli of urothelial cells were found within 1-2 months after TUR. In conclusion, cytological changes induced by BCG therapy are nonspecific and reactive in nature, different from those due to chemotherapeutic agents and distinguishable from malignant changes of urothelial cells.