[THE EFFECT OF LOW-DOSE INTRAVESICAL BACILLUS CALMETTE-GUÉRIN (BCG) INFUSION THERAPY FOR NON-MUSCLE INVASIVE BLADDER CANCER].

(Objective) Bacillus Calmette-Guérin (BCG) intravesical infusion therapy plays an important role in the treatment of patients with high-risk non-muscle-invasive bladder cancer (NMIBC). Our institute performs low-dose (40 mg) BCG intravesical infusion therapy (completed 8 times) to reduce side effects. We retrospectively investigated its efficacy and side effects. (Patients and methods) We analyzed the response, non-recurrence, and side effect rates by risk stratification in 179 patients who received low-dose BCG intravesical infusion therapy from September 2003 to November 2018 in Nagano Municipal Hospital. Complications were classified using the Common Terminology Criteria for Adverse Events version 4.0. (Results) The median age was 73 years, and the male/female ratio was 137:42. The median observation period was 32 months, and infusion was completed 8 times in 149 cases (83.2%). The overall response rate was 88.8%. The response rate was significantly higher in the low-grade pathology group than in the high-grade group. However, no significant differences in G1/G2/G3 side effects, sex, age, presence of carcinoma in situ (CIS), depth of invasion, purpose of administration, and grade of side effects were observed. The overall non-recurrence rates were 91.8%, 76.7%, and 71.3% at 1, 3, and 5 years, respectively. Nevertheless, there were no significant differences in the non-recurrence rates with respect to depth of penetration, the degree of dysmorphism, purpose of administration, presence of CIS, and completed of infusion. A total of 71 G2 side effects (39.7%) were identified, and 3 cases of G3 side effects required hospitalization. (Conclusion) In our institution, the completion rate of low-dose BCG intravesical infusion therapy was high, with few side effects. Furthermore, it demonstrated similar therapeutic effect to that reported with standard-dose administration. Low-dose BCG intravesical infusion therapy may be an effective treatment, particularly for pathologically low-grade NMIBC.