Bladder cancer is a prevalent malignancy, particularly affecting men. An unexpected connection exists between bladder cancer treatment and a microorganism typically associated with tuberculosis. Bacillus Calmette-Guérin (BCG) therapy utilizes a modified form of tuberculosis bacteria to combat cancerous cells within the bladder.
Bladder Cancer: An Overview
Bladder cancer commonly presents with symptoms such as blood in the urine. It has a high recurrence rate, especially in early stages, even after initial removal. For tumors that have not invaded the bladder muscle, termed non-muscle invasive bladder cancer (NMIBC), local treatments are frequently employed. Intravesical therapy, administering medication directly into the bladder, is common for these early-stage cancers. This localized delivery targets cancer cells lining the bladder wall.
BCG Therapy: The Tuberculosis Connection
Bacillus Calmette-Guérin (BCG) is a weakened strain of Mycobacterium bovis, related to the bacterium causing human tuberculosis. The BCG used in cancer treatment is attenuated, meaning it does not cause active tuberculosis. Originally a tuberculosis vaccine, BCG’s immune-stimulating ability led to its discovery as an effective bladder cancer treatment in the 1970s. Since then, BCG has become a standard and effective immunotherapy, primarily used for non-muscle invasive bladder cancer, typically after the tumor has been surgically removed.
How BCG Targets Bladder Cancer
When BCG is introduced into the bladder, it attaches to the bladder wall and initiates a localized immune response. This interaction stimulates the body’s immune system, recruiting various immune cells such as T-cells, natural killer cells, and macrophages to the bladder lining. These activated immune cells then recognize and attack the cancerous cells, rather than BCG directly eliminating them. The process involves the release of signaling molecules called cytokines, including interleukin-2, interleukin-8, and tumor necrosis factor-alpha, which orchestrate this anti-tumor activity. BCG can also directly interact with and be internalized by cancer cells, prompting them to act as antigen-presenting cells that further activate the immune system.
What to Expect During and After BCG Treatment
BCG therapy is administered directly into the bladder via a catheter inserted through the urethra. Patients are typically asked to hold the liquid medication in their bladder for up to two hours to ensure it contacts the bladder lining. A common treatment schedule involves an initial “induction course” of weekly instillations for six weeks. If the treatment proves effective, a “maintenance therapy” may follow, consisting of shorter courses given periodically over one to three years to prevent recurrence.
Common side effects are usually localized to the bladder and temporary, including frequent urination, a burning sensation during urination, and sometimes a small amount of blood in the urine. Flu-like symptoms such as fatigue, muscle pain, and a low-grade fever can also occur, typically resolving within a few days. Healthcare providers offer guidance on managing these effects, and patients are advised on precautions to prevent the spread of live bacteria, such as specific toilet hygiene for several hours post-treatment. Regular monitoring, including cystoscopies, is conducted after treatment to check for any signs of cancer recurrence.