Individuals with high-risk non-muscle invasive bladder cancer who receive at least five doses of Bacillus Calmette−Guérin (BCG) maintenance therapy experience improved recurrence-free survival, according to a study recently published in Urologic Oncology: Seminars and Original Investigations.
BCG treatment is a form of immunotherapy delivered directly to the bladder to target and attack bladder cancer cells. It uses a weakened form of Myocobacterium bovis, which stimulates the immune system to destroy the cells. It can be given both as an initial treatment following surgery to remove tumors (called induction therapy), and as as an ongoing treatment to prevent bladder cancer recurrence and progression, called maintenance therapy.
While BCG maintenance therapy has shown to be effective in high-risk non-muscle invasive bladder cancer, many patients do not complete all the recommended treatment sessions.
To better understand how the number of BCG maintenance therapy sessions affected outcomes, the researchers studied 150 patients who received transurethral resection of bladder tumor (TURBT) and BCG treatment at Kobe University Hospital in Kobe, Japan. The authors defined adequate BCG maintenance therapy as five or more sessions (out of the nine total planned) within one year.
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Overall, 51.3% of participants received an adequate dose, and 48.7% received an inadequate dose. Furthermore, 17 patients completed treatment, defined as receiving the full nine installations over one year.
At the start of treatment, individuals receiving an adequate dose had a higher estimated probability of remaining recurrence-free at five years (85.9%) than those receiving an inadequate dose (63.9%).
In statistical models, the benefits of adequate maintenance therapy intensity were strongest within the first year after treatment initiation. At 18 and 24 months, the strength of the association between treatment intensity and recurrence-free survival decreased.
Other clinical factors, including age, sex, the presence of multiple tumors and tumor size did not significantly predict recurrence-free survival.
While more participants receiving an adequate dose experienced side effects, this difference was not significantly different between groups. Common adverse events in both groups included frequent urination, painful urination, blood in the urine and fever.
“These findings underscore the importance of treatment adherence to achieve optimal clinical outcomes,” the authors concluded. “While further prospective research is warranted, our results strongly support the benefit of adequate BCG maintenance intensity in improving recurrence control among high-risk non-muscle invasive bladder cancer.”
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