Are there Time-period-related Differences in the Prophylactic Effects of Bacille Calmette-Guérin Intravesical Instillation Therapy in Japan?

Objective: The guidelines on indications for prophylactic use of Bacille Calmette-Guérin (BCG) against nonmuscle-invasive bladder cancer (NMIBC) have changed over the years. In order to assess the impact on outcome,the present retrospective comparison of BCG efficacy by time period with Japanese patients was conducted.Patients and
Methods: A total of 146 cases of NMIBC treated with BCG since February 1985 were retrospectivelyevaluated. All patients received 80 mg of BCG (Tokyo 172 strain) six to eight times a week for prophylactic use.Comparison was made among three historical groups (Group A: 1980’s, 39 cases; Group B: 1990’s, 61 cases;Group C: 2000’s, 46 cases).
Results: In total, recurrence was seen in 55 of the 146 cases (37.7%), and progressionin 14 (9.6%), 1 patient dying of cancer. These overall results were similar to those outlined in previous reports.However, the outcomes of this time-period-based analysis indicated a tendency for a shorter time to recurrencein patients after 2000, although a log-rank test showed no significance (P=0.229). Seven of the cases featuringprogression (i.e., half of all such cases) were among the 46 Group C patients (15.2%). Excluding these progressivecases, there was no significant difference among the remaining 132 patients in the three groups.
Conclusion:This study results revealed a tendency for a lower non-recurrence rate after 2000 in our series. This could stemfrom a number of factors, including changes in BCG indication criteria and the evolution of histopathologicaldiagnostic criteria.