Leukocyturia as a predictor of tolerance and efficacy of intravesical BCG maintenance therapy for superficial bladder cancer

Abstract

Objectives. To examine leukocyturia as a predictor of tumor recurrence and occurrence of adverse events after bacille Calmette-Guérin (BCG) immunotherapy. The use of BCG immunotherapy, a very major advance in the management of superficial bladder cancer, is limited by the frequency of adverse events. As yet, we have no way of predicting the efficacy and tolerability of BCG instillation in clinical practice. This problem is even more acute during BCG maintenance therapy. Methods. Adverse events in 72 patients who received 518 instillations were prospectively assessed using a four-class scale based on severity and duration. Urinary leukocytes were counted 3 days after each instillation, using the KOVA-Slide 10 method. Results. High leukocyturia during BCG treatment (cutoff value 1.65 × 10 5/mL urine) correlated with recurrence-free status ( P = 0.009). The degree of leukocyturia correlated with the severity/duration of adverse events ( P <0.0001); the median leukocyturia values associated with class I, II, and III adverse events were 4 × 10 4/mL, 1.5 × 10 5/mL, and 3.5 × 10 5/mL, respectively. No class IV events occurred. The cutoff point indicating treatment cessation for adverse events was leukocyturia of 8.6 × 10 4/mL. Conclusions. These results suggest a link between adverse events and efficacy during BCG maintenance therapy. Leukocyturia appears to correlate with both efficacy and tolerability in this setting. Prospective randomized studies are required to evaluate leukocyturia as a basis on which to adapt the BCG instillation schedule to individual patient susceptibility.