Bladder cancer is a common malignancy that begins in the cells lining the bladder, most often the urothelial cells. Treatment for this disease has evolved significantly beyond surgery and chemotherapy, with immunotherapy emerging as a powerful approach. This treatment harnesses the body’s own defense mechanisms, the immune system, to recognize and eliminate cancer cells. Immunotherapy represents a distinct treatment strategy, teaching the body to fight the cancer. This guide provides an overview of what to expect when undergoing immunotherapy for bladder cancer.
Types of Immunotherapy Used for Bladder Cancer
The type of immunotherapy used for bladder cancer depends primarily on the stage and characteristics of the disease.
Non-Muscle Invasive Bladder Cancer (NMIBC)
For cancers that have not yet invaded the deep muscle layer of the bladder wall, known as NMIBC, the standard initial immunotherapy is Bacillus Calmette-Guérin (BCG). BCG is a weakened strain of Mycobacterium bovis, the same bacterium used in the tuberculosis vaccine. This agent is administered directly into the bladder, creating a localized inflammatory response that activates immune cells to attack the cancer. The immune cascade involves the activation of T-cells and natural killer cells, which are directed to the bladder lining to destroy the malignant cells.
Advanced Bladder Cancer
For more advanced forms of the disease, such as muscle-invasive or metastatic bladder cancer, immune checkpoint inhibitors (ICIs) are used. These systemic therapies target specific proteins on immune cells, such as PD-1 or PD-L1, which typically act as “brakes” to prevent the immune system from attacking healthy cells. Cancer cells can exploit this natural mechanism to hide from immune surveillance. By blocking this interaction, checkpoint inhibitors “release the brakes,” allowing T-cells to become fully activated and recognize the cancer as a threat. These inhibitors are often employed when the cancer has progressed despite chemotherapy or for patients who are unable to tolerate traditional chemotherapy regimens.
The Treatment Process and Schedule
The administration process for bladder cancer immunotherapy varies significantly depending on whether the treatment is local or systemic.
BCG Instillation
Bacillus Calmette-Guérin is delivered via intravesical instillation, meaning the liquid drug is placed directly into the bladder using a catheter. Patients are often advised to restrict fluid intake beforehand to ensure the bladder is empty and the drug is not immediately diluted. Once the BCG solution is in the bladder, the catheter is removed. The patient must retain the liquid for one to two hours, allowing the agent to contact the bladder lining and initiate the desired immune reaction.
The standard schedule for BCG begins with an induction course of one weekly instillation for six consecutive weeks. Following this, a maintenance schedule is recommended for high-risk patients to reduce the risk of recurrence and progression. Maintenance therapy typically involves three weekly treatments at months three, six, and twelve, which may continue for up to three years.
Checkpoint Inhibitor Infusion
Systemic immune checkpoint inhibitors are administered intravenously (IV) through a vein, usually in an outpatient infusion center. This method ensures the drug enters the bloodstream and circulates throughout the body to target cancer cells. The frequency of these infusions depends on the specific drug used, but a common schedule is typically every two, three, or four weeks. Treatment can extend for many months or until the disease progresses, and timing is determined by the treating oncologist.
Recognizing and Managing Side Effects
Immunotherapy engages the immune system, leading to a range of side effects that differ significantly between the two main types of treatment.
BCG Side Effects
With intravesical BCG, adverse events are primarily localized to the bladder and mimic the symptoms of a urinary tract infection. Common side effects include pain or a burning sensation during urination, increased urinary frequency and urgency, and sometimes blood in the urine. These irritative symptoms usually begin shortly after instillation and typically subside within 24 to 48 hours. Systemic side effects are also possible, presenting as flu-like symptoms such as a low-grade fever, chills, and general muscle or joint aches. Management involves over-the-counter pain relievers or prescribed medications to ease bladder spasms. If a high fever persists or symptoms do not improve after a few days, contact the care team immediately, as this could indicate a systemic BCG infection.
Checkpoint Inhibitor Side Effects (IRAEs)
Immune checkpoint inhibitors cause a distinct set of side effects known as immune-related adverse events (IRAEs). These occur because the activated immune system may mistakenly attack healthy organs and tissues throughout the body. The type and severity of IRAEs vary, but they can affect almost any organ system.
Common IRAEs include:
- Skin issues, such as a rash or itching.
- Gastrointestinal issues, leading to diarrhea or colitis (inflammation of the colon).
- Pneumonitis (lung inflammation).
- Hepatitis (liver inflammation).
- Endocrine issues, such as thyroid gland dysfunction.
Prompt reporting of any new or worsening symptom is necessary for effective management. Management depends on severity; mild reactions may be observed or treated with topical creams. Moderate to severe IRAEs often require temporarily pausing the immunotherapy and using corticosteroids, such as prednisone, to suppress the immune response. If the adverse event is severe, the immunotherapy may need to be permanently discontinued.
Assessing Treatment Success and Follow-Up Care
Determining the success of bladder cancer immunotherapy involves a rigorous and long-term surveillance strategy.
For NMIBC treated with BCG, initial success is assessed through procedures like cystoscopy, where a camera inspects the bladder lining for recurrent tumors. Urine cytology, which checks for malignant cells, and periodic biopsies are also used to confirm the response. Success is defined by a “complete response” (no evidence of cancer) or “disease stability” (the tumor has not progressed).
For advanced disease treated with checkpoint inhibitors, success is evaluated using imaging tests like CT or MRI scans to measure changes in tumor size. A positive outcome can be a complete response, a “partial response” (significant tumor shrinkage), or durable stabilization of the disease.
Long-term follow-up care is required due to the high potential for recurrence. The surveillance schedule is intensive, typically involving a cystoscopy every three to six months for the first few years. If immunotherapy fails to control the cancer, subsequent options may include chemotherapy, radical cystectomy (bladder removal), or clinical trial treatments.