Bacillus Calmette-Guérin (BCG) immunotherapy is the standard treatment for non-muscle-invasive bladder cancer (NMIBC) following initial tumor removal. This treatment involves instilling a solution containing a weakened form of Mycobacterium bovis directly into the bladder to stimulate a localized immune response against cancer cells. Following BCG therapy, patients enter a crucial monitoring period. Cystoscopy is a minimally invasive procedure that allows a urologist to look inside the bladder using a thin, flexible scope with a camera. This ongoing surveillance is necessary to quickly identify any cancer cells that may return, ensuring the best possible long-term outcome.
Why Surveillance is Necessary After BCG
Non-muscle-invasive bladder cancer (NMIBC) is known for its high rate of recurrence, meaning the cancer can return even after successful initial treatment. Without additional therapy following tumor removal, the recurrence rate for NMIBC can range from 50% to 70%, especially for higher-risk tumors. BCG is an effective form of immunotherapy designed to significantly reduce this risk. However, BCG is not a guaranteed cure, and around 30% to 45% of patients who receive the therapy may still experience a recurrence of their cancer.
The main goal of post-BCG surveillance is to detect recurrence before the disease progresses to a more serious stage. Progression occurs when the cancer grows deeper into the muscle layer of the bladder wall, which is a life-threatening event that significantly worsens the prognosis. For patients with high-risk NMIBC, the risk of progression is about 14% at ten years, underscoring the need for close and continuous observation. Early detection through regular cystoscopies allows for timely intervention, which is the most effective way to preserve the bladder and improve survival rates.
What to Expect During the Procedure
A cystoscopy is typically performed in an outpatient clinic setting using a flexible scope. Before the examination, you will be asked to empty your bladder, and a urine sample may be collected to check for infection. If an active infection is present, the procedure may need to be postponed to prevent the risk of spreading bacteria into the bloodstream. Some doctors may also prescribe a short course of antibiotics before or after the procedure, particularly for patients at higher risk of infection.
Once positioned comfortably, a numbing gel is applied to the opening of the urethra. This local anesthetic is allowed a few minutes to take effect, minimizing discomfort as the thin, flexible cystoscope is gently inserted through the urethra and advanced into the bladder. Sterile fluid, such as saline, is then used to fill the bladder, expanding the walls for a clearer view of the lining. As the bladder fills, you may feel a normal, temporary sensation similar to the need to urinate. The actual time the scope is inside the bladder is usually very short, often lasting only 10 to 15 minutes.
Distinguishing BCG Side Effects from Recurrence
A unique challenge in monitoring after BCG treatment is that the immunotherapy causes significant inflammation in the bladder lining, known as granulomatous cystitis. This intense immune response can visually mimic the appearance of early cancer recurrence. Common post-BCG findings that are benign reactions include areas of redness, scarring, or small, raised lesions called granulomas, which are essentially clumps of immune cells. Distinguishing these harmless changes from actual tumor cells is difficult using visual inspection alone.
BCG-induced inflammation causes urothelial cells to undergo morphologic alterations, leading to reactive atypia that is challenging to interpret visually. For example, aggressive carcinoma in situ (CIS) and patches of post-BCG inflammation can both appear as flat, red areas on the bladder wall. If the urologist observes any suspicious lesions during the cystoscopy, a biopsy is necessary to definitively determine if the changes are benign or cancerous. Advanced techniques like blue light cystoscopy or narrow band imaging may also be used, as they enhance the visualization of abnormal tissue and help detect subtle recurrences.
Interpreting Results and Ongoing Monitoring
The results of your surveillance cystoscopy will generally fall into one of three categories, which dictate the necessary next steps in your care and monitoring schedule:
- A clear or negative outcome means the urologist found no evidence of recurrence, and you will continue on the standard surveillance schedule.
- If the findings are suspicious or atypical, the urologist will typically proceed with a biopsy of the concerning area, often combined with a urine cytology test to look for malignant cells.
- Finally, a confirmed recurrence means that cancerous cells have been found, necessitating a new treatment plan.
The standard surveillance schedule is aggressive, particularly in the first few years due to the high risk of recurrence. Cystoscopies are typically performed every three months for the first two years after BCG treatment. The frequency then decreases to every six months until five years have passed, and subsequently annually for an indefinite period. If recurrence is confirmed, subsequent treatment options may involve a repeat course of BCG, a different intravesical therapy, or, in cases of BCG-unresponsive disease or progression, a more radical procedure such as a cystectomy (bladder removal).