Bladder cancer begins when cells in the bladder’s lining grow abnormally. Superficial bladder cancer, also known as non-muscle invasive bladder cancer (NMIBC), is a common type characterized by its confinement to the inner lining of the bladder. This means it has not penetrated the deeper muscle wall, a distinction that affects its prognosis and treatment approaches.
Understanding Superficial Bladder Cancer
Superficial bladder cancer (NMIBC) affects only the urothelium, the innermost lining of the bladder. This cancer has not grown into the underlying muscle layer of the bladder wall. NMIBC is the most frequently diagnosed bladder cancer, accounting for approximately 75% of new cases.
NMIBC is classified by how deeply the cancer has grown into the bladder lining. Ta tumors are papillary, resembling small mushrooms, confined to the urothelium. T1 tumors have grown through the urothelium into the lamina propria, the connective tissue layer beneath the lining, but not the muscle. Carcinoma in situ (CIS), also known as Tis, is a flat, high-grade cancer appearing as a reddish patch. CIS is considered more aggressive despite being superficial, as it carries a higher risk of progressing to muscle-invasive disease.
Factors that increase the risk of developing bladder cancer include smoking, which is the most significant, contributing to at least half of all new cases. Chemicals from tobacco smoke damage the bladder lining over time. Occupational exposure to certain industrial chemicals, such as aniline dyes and benzidine, found in industries like paint, rubber, and textiles, also elevates risk. Other risk factors include long-term use of certain chemotherapy drugs like cyclophosphamide, chronic bladder irritation from infections or catheters, and a family history of bladder cancer.
Recognizing the Signs and Getting Diagnosed
The most common sign of superficial bladder cancer is hematuria, which is blood in the urine. This blood may be visible, causing the urine to appear pink, red, or brown, or it might be microscopic and only detected during a routine urine test. The presence of blood in urine can be intermittent, appearing and disappearing over weeks or months.
Other symptoms include frequent urination, a strong urge to urinate even when the bladder is not full, and pain or a burning sensation during urination (dysuria). While these symptoms are often associated with less serious conditions like urinary tract infections or kidney stones, their persistence warrants medical evaluation. In women, bladder cancer symptoms can sometimes be mistaken for urinary tract infections, potentially delaying diagnosis.
When bladder cancer is suspected, diagnostic tests are performed. These often include a urinalysis to check for blood or bacteria, and urine cytology, where a pathologist examines a urine sample under a microscope for cancer cells. Urine cytology is highly specific for detecting high-grade tumors (over 90%), but its sensitivity for low-grade tumors can be as low as 10-50%, meaning it can miss many such cases.
Cystoscopy is the primary diagnostic tool for bladder cancer. During this procedure, a thin tube with a light and camera (cystoscope) is inserted through the urethra into the bladder, allowing the doctor to visually inspect the bladder lining. If suspicious areas are found, a biopsy, known as a transurethral resection of bladder tumor (TURBT), is typically performed to obtain tissue samples for examination and confirm the diagnosis. Imaging scans, such as a CT urogram, may also be used to provide detailed views of the urinary tract, including the kidneys, ureters, and bladder, to help identify tumors and assess for any spread.
Treatment Approaches
The primary treatment for superficial bladder cancer is transurethral resection of bladder tumor (TURBT). This surgical procedure uses a resectoscope, a thin, rigid cystoscope with a wire loop, inserted through the urethra into the bladder. The surgeon uses the wire loop to cut away visible tumors from the inner lining of the bladder, along with some surrounding bladder wall tissue to ensure complete removal. The removed tissue is then sent to a laboratory for pathological analysis to determine the cancer’s stage and grade. In some instances, a second TURBT may be performed a few weeks later to ensure all cancerous cells are removed, particularly for high-grade or T1 tumors.
Following TURBT, intravesical therapies are often administered directly into the bladder to reduce the risk of cancer recurrence. Bacillus Calmette-Guérin (BCG) is a common intravesical immunotherapy, made from a weakened strain of bacteria related to tuberculosis. When instilled into the bladder via a catheter, BCG stimulates the body’s immune system to target and destroy bladder cancer cells. BCG is typically given as a weekly treatment for six weeks, starting approximately two to four weeks after TURBT, and is particularly effective for high-risk cases, including carcinoma in situ (CIS), where it can eradicate the cancer in over 80% of cases.
Intravesical chemotherapy agents, such as mitomycin C and gemcitabine, are also used. These drugs are delivered directly into the bladder through a catheter and work by killing actively growing cancer cells. Mitomycin C can reduce the chance of bladder tumors returning by up to 50% and is often used for lower-risk cases or as an alternative to BCG. Gemcitabine is another chemotherapy agent that can help prevent tumor recurrence, often with mild side effects. These intravesical treatments localize the drug’s effect to the bladder lining, minimizing systemic side effects that might occur with intravenous chemotherapy.
Managing Recurrence and Long-Term Care
Superficial bladder cancer has a notable tendency to recur, with rates ranging from 15% to 70% within two years after initial treatment. More than half of individuals treated for bladder cancer may experience a recurrence, necessitating ongoing surveillance to detect any new tumors early.
Long-term care involves a structured follow-up schedule, primarily consisting of regular cystoscopies and urine tests. For low-risk Ta tumors, cystoscopy might be recommended at 3 and 12 months, then annually for five years. For intermediate and high-risk NMIBC, cystoscopy with urine cytology is generally recommended every three to four months for the first two years, then every six months for years three and four, and annually thereafter, potentially lifelong for high-risk cases.
The purpose of this rigorous surveillance is to detect recurrence or progression, which is when non-muscle invasive bladder cancer advances to become muscle-invasive. While most recurrences remain superficial, between 10% and 30% of NMIBC cases, particularly high-grade tumors, may progress to muscle-invasive bladder cancer, a more aggressive form of the disease. Early detection of progression through consistent follow-up allows for timely intervention, such as radical cystectomy (bladder removal), if needed. Patients are encouraged to adhere to their follow-up protocols and maintain healthy lifestyle choices to support their long-term management.