BCG instillation is a common treatment for bladder cancer, involving the direct introduction of a liquid medication into the bladder. This intravesical therapy is a type of immunotherapy, meaning it works by stimulating the body’s own immune system. It offers a targeted approach to address cancer cells within the bladder lining.
Understanding BCG and Its Use
BCG, or Bacillus Calmette-Guérin, is a weakened form of Mycobacterium bovis, the bacterium that causes tuberculosis. Though initially a vaccine, this weakened bacterium is now used to treat certain cancers. When instilled into the bladder, BCG stimulates the local immune system to recognize and attack cancer cells. This activation involves various immune cells, including T cells, natural killer (NK) cells, macrophages, and granulocytes, which collectively work to eliminate cancerous cells.
BCG is primarily used for non-muscle invasive bladder cancer (NMIBC), including carcinoma in situ (CIS) and other early-stage tumors that have not penetrated the bladder muscle wall. This treatment is suitable because the medication directly contacts superficial cancer cells lining the bladder. It is a widely accepted first-line treatment, especially after surgical removal of visible tumors, to reduce cancer recurrence and progression.
The Treatment Process
Before a BCG instillation, patients typically receive specific instructions to prepare, such as limiting fluid intake for at least two hours to ensure the solution remains concentrated and in the bladder for the intended duration. A urine check for infections is also conducted on the day of the procedure, as treatment may be postponed if an infection is present. Patients are asked to empty their bladder completely just before the instillation.
During the procedure, a healthcare provider inserts a thin, flexible tube called a catheter through the urethra into the bladder. The liquid BCG solution is then slowly instilled into the bladder through this catheter. After the solution is administered, the catheter is usually removed, and the patient is instructed to hold the BCG in their bladder for approximately two hours. Patients may be asked to change positions every 15-30 minutes during this time to ensure the solution evenly contacts all areas of the bladder lining.
After the retention period, the patient empties their bladder. Post-instillation care involves specific precautions for about six hours due to the live bacteria. These include sitting down to urinate to prevent splashing and adding two cups of undiluted bleach to the toilet bowl, letting it sit for 15-20 minutes before flushing. Drinking plenty of fluids after treatment helps to flush the BCG from the system.
Treatment Schedule
The typical treatment schedule begins with an “induction course” of six weekly treatments. If the initial course is effective, “maintenance therapy” may follow. This often involves less frequent treatments, such as three weekly treatments at 3, 6, and 12 months, potentially continuing for up to three years to prevent recurrence.
Managing Side Effects
BCG instillation can lead to various side effects, which are generally a result of the immune system’s response to the bacteria within the bladder. Common side effects include bladder irritation, a frequent urge to urinate, discomfort during urination, and sometimes blood in the urine. These symptoms typically begin within a few hours of instillation and may last for up to 48-72 hours. Patients might also experience flu-like symptoms such as fatigue, mild fever (below 101°F or 38.5°C), chills, and body aches.
Managing these common side effects often involves practical measures at home. Over-the-counter pain relievers can help with discomfort, and maintaining good hydration by drinking plenty of fluids can help dilute the urine and flush the bladder. Resting can also alleviate general malaise and fatigue. It is important to contact a healthcare provider if symptoms do not resolve within a few days or if they worsen.
Less common but more severe side effects require immediate medical attention. These include a persistent high fever (102°F or 39°C or above), severe abdominal pain, or significantly painful urination that does not subside. Systemic BCG infection, also known as BCGitis, is a serious but rare complication where the bacteria spread beyond the bladder, potentially affecting other organs. Such severe reactions, though infrequent, necessitate urgent treatment with specific medications.
Effectiveness and Patient Outlook
BCG instillation is the most effective intravesical treatment for non-muscle invasive bladder cancer. While success rates vary by cancer grade and stage, studies show BCG treatment can eradicate carcinoma in situ (CIS) in approximately 70% of patients who meet specific criteria.
Despite its efficacy, some patients may experience recurrence, with figures suggesting up to 40% of individuals might see the cancer return after BCG treatment. Even if cancer recurs, it may not necessarily progress to a more invasive stage, especially for low-grade forms. However, aggressive bladder cancer can develop in some cases after BCG treatment, which might necessitate more invasive procedures.
Regular follow-up appointments are a cornerstone of post-BCG care to monitor for any signs of cancer recurrence. These typically involve cystoscopy, where a thin camera examines the bladder, and urine cytology tests. If BCG treatment is not fully effective, alternative therapies or more invasive procedures, such as radical cystectomy (surgical removal of the bladder), may be considered, particularly for high-risk cases that show resistance to BCG.