Bacillus Calmette-Guérin (BCG) monotherapy is associated with better long-term efficacy than alternating therapy with mitomycin C (MMC) and BCG in patients with carcinoma in situ of the bladder, according to a new study.
The finding is from a study of 321 CIS patients from Finland, Norway, and Sweden enrolled in a prospective multicenter trial and randomized to receive either BCG monotherapy or alternating MMC/BCG therapy. After a median follow-up of 9.9 years (maximum 19.9 years) in the BCG monotherapy arm and 8.9 years (maximum 20.3 years) in the alternating treatment arm, investigators found that the risk of disease recurrence was significantly lower in the BCG monotherapy arm than the alternating treatment arm (49% vs. 59%) at 15 years). This difference in recurrence rates corresponded to a significant 26% decreased risk of recurrence, investigators led by Eero Kaasinen, MD, of Helsinki University Hospital in Helsinki, Finland, reported in the Scandinavian Journal of Urology (2016;50:360-368). The researchers observed no significant difference in progression risk and disease-specific and overall mortality between the groups.
Patients who experienced disease progression after 2 years compared with before 2 years had a significantly higher risk of dying from bladder carcinoma (77% vs. 35%), according to the researchers.
The study also showed that patients with primary CIS had a significant increased risk of recurrence compared with those who had comcomitant CIS.
In addition, Dr. Kaasinen’s team found that patients in the MMC/BCG group were significantly less likely to terminate in the instillation regimen prematurely because of adverse effects. The probability of non-cessation of instillations at 6, 12, and 15 months for MMC/BCG vs BCG alone was 99% vs. 90%, 95% vs. 75%, and 94% vs. 73%, respectively.
Alternating therapy consisted of 6 weekly instillations of mitomycin C 40 mg followed by 10 instillations of BCG or MMC alternating monthly for 1 year. The same 6 + 10 schedule was followed for BCG monotherapy.
In an accompanying editorial, Kesavan Esuvaranathan, MD, of the National University of Singapore, wrote: “Kaasinen and colleagues are to be congratulated for contributing one of the best descriptions of the long-term, treatment-modified history of carcinoma in situ (CIS) of the bladder.”