What is the role of intravesical Bacillus Calmette-Guérin (BCG) in carcinoma of the bladder?

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Last updated: April 3, 2025View editorial policy

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From the Guidelines

Intravesical BCG therapy is the recommended first-line treatment for high-risk non-muscle invasive bladder cancer (NMIBC), as it has been shown to decrease the risk of bladder cancer recurrence following transurethral resection of the bladder tumor (TURBT) 1. The standard regimen typically involves an induction course of weekly instillations for 6 weeks, followed by maintenance therapy with 3 weekly instillations at months 3,6,12,18,24,30, and 36 for optimal efficacy.

  • BCG is particularly effective for carcinoma in situ (CIS), high-grade Ta tumors, and T1 tumors, reducing recurrence rates by approximately 70% and progression rates by about 30% 1.
  • The mechanism involves both innate and adaptive immune responses, with BCG adhering to urothelial cells, triggering inflammation, and recruiting immune cells that target cancer cells.
  • Common side effects include urinary frequency, dysuria, and mild hematuria, while serious complications like BCG sepsis are rare but require immediate attention 1.
  • Patients should avoid urination for 2 hours after instillation and should be monitored for persistent fever, severe hematuria, or systemic symptoms.
  • For patients who are BCG-unresponsive, alternative treatments such as radical cystectomy, thermo-chemotherapy, or intravenous pembrolizumab may be considered 1.
  • BCG therapy should be prioritized as the initial treatment for high-risk NMIBC due to its proven efficacy in reducing recurrence and progression rates, as supported by the most recent guidelines from the National Comprehensive Cancer Network (NCCN) 1.

From the FDA Drug Label

The precise mechanism of action is unknown. The role of intravesical BCG in carcinoma in situ (CIS) of the bladder is to induce a granulomatous reaction at the local site of administration, which has been used as a therapy for, and prophylaxis against, recurrent tumors in patients with CIS of the urinary bladder, and to prevent recurrence of Stage TaT1 papillary tumors of the bladder at high risk of recurrence 2.

  • Key points:
    • Induces a granulomatous reaction
    • Used for therapy and prophylaxis of CIS and TaT1 tumors
    • Mechanism of action is unknown The studies show that intravesical BCG can achieve a complete response in some patients with CIS, with a median duration of response estimated at 4 years or greater 2, 2.

From the Research

Role of Intra-Vesicle BCG in Ca Bladder

  • Intra-vesical Bacillus Calmette-Guérin (BCG) is a standard conservative treatment for patients with high-risk non-muscle-invasive bladder cancer (NMIBC) 3, 4, 5.
  • BCG has been shown to reduce recurrence and delay progression among patients with high-risk NMIBC, but is associated with a substantial emotional, physical, and social burden 6.
  • The optimal dose, induction, and maintenance schedules, and duration of BCG treatment are unknown and may vary for each patient 4, 7.
  • Maintenance BCG is required to achieve the best therapeutic results, but the role of BCG in disease progression remains controversial 3, 4, 5.
  • BCG is the most effective intravesical agent for preventing NMIBC recurrence, but its impact on the natural history of T1G3 tumors relies on a low level of evidence 5.
  • Patients failing BCG treatment have a poor prognosis, and cystectomy is then the recommended treatment 3, 4.

Treatment Options for BCG Failure

  • Radical cystectomy (RC) should be strongly recommended when a patient has been deemed to fail BCG, if the patient is fit and fully informed of the risks, benefits, and quality-of-life issues 3.
  • Other salvage intravesical therapies, such as immunotherapy, chemotherapy, device-assisted therapy, and sequential combinations of these newer modalities with conventional therapy, can be considered if bladder preservation is the objective 3.
  • Some agents, such as gemcitabine, thermochemotherapy, and taxane chemotherapy, have shown promise in BCG-failure patients 3.

Adherence to BCG Treatment

  • Most patients with NMIBC treated with first-line intravesical BCG receive adequate BCG induction, but less than half have adequate BCG maintenance 6.
  • BCG treatment is also inadequate for patients with carcinoma in situ (CIS), with only half of patients receiving adequate BCG maintenance and a higher proportion undergoing cystectomy following first-line BCG 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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