Are there time-period-related differences in the prophylactic effects of Bacille Calmette-Guerin intravesical instillation therapy in Japan?

ABSTRACT

OBJECTIVE: The guidelines on indications for prophylactic use of Bacille Calmette-Guerin (BCG) against non- muscle-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 retrospectively evaluated. 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 progression in 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 recurrence in patients after 2000, although a log-rank test showed no significance (P=0.229). Seven of the cases featuring progression (i.e., half of all such cases) were among the 46 Group C patients (15.2%). Excluding these progressive cases, 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 stem from a number of factors, including changes in BCG indication criteria and the evolution of histopathological diagnostic criteria.