What causes bladder cancer?
Smoking is the most common cause of bladder cancer. Patients who smoke or have smoked in the past have a 2 to 4-fold increased risk of developing bladder cancer. This risk increases in people who smoke frequently and over a long period of time, and can persist for up to thirty years after quitting cigarettes.
Patients who have had longstanding inflammation or irritation of the bladder can also develop bladder cancer. This includes patients who have had catheters for a long time, who have bladder stones that have not been treated, or who have had persistent problems with urinary tract infections. These patients tend to develop squamous cell rather than urothelial cell carcinoma.
Exposure to certain chemicals and dyes increases the risk of bladder cancer. Occupations with an increased risk of bladder cancer include textile workers, printers, tire/rubber workers, dye leather workers, painters, dry cleaners and hairdressers.
Patients who have had radiation therapy to other organs in the pelvis may develop bladder cancer after several years. The chemotherapy drug cyclophosphamide can also cause bladder cancer, usually between 6 to 13 years after it is given.
How is bladder cancer diagnosed?
Bladder cancer patients usually present with blood in the urine. This can be either blood that the patient sees, or blood that is picked up after microscopic examination of the urine. Infrequently, patients may also show symptoms of bladder irritation, such as the urge to go to the toilet frequently or burning pain when passing urine.
All patients who have blood in the urine must have imaging of the kidneys and ureters, usually in the form of a CT intravenous pyelogram, as well as a cystoscopy. A cystoscopy involves passing a small telescope into the bladder via the urethra.
How is bladder cancer treated?
The treatment of bladder cancer depends upon how aggressive it is (called “grade”) and how far it has advanced within and beyond the bladder (called “stage”). These factors determine the likelihood of the cancer coming back after it has been removed, and also the likelihood of it spreading beyond the bladder.
To work out grade and stage, a patient first needs a transurethral resection of bladder tumour (TURBT). In this operation special instruments are passed down the urethra to the bladder via a telescope. The tumour is cut out using these instruments and the pieces are extracted via the telescope. A pathologist then examines the tumour pieces under a microscope.
For tumours confined to the innermost lining of the bladder, not invading the muscle layer, treatment will depend upon factors such as the grade of the tumour, its size, the presence of multiple tumours, and the pattern of prior recurrences. In most of these cases the patients will require repeat cystoscopies over an extended period of time to check for recurrences.
If the cancer is found to be invading into the muscle of the bladder wall, then the entire bladder needs to be removed surgically. This operation involves removing the bladder, the pelvic lymph glands, the prostate and seminal vesicles in men, and the uterus, ovaries and anterior vagina in women.
Ideally a course of chemotherapy is undertaken prior to removal of the bladder, the goal of which is to destroy microscopic foci of cancer outside the surgical excision field.
If the bladder is removed, where does the urine go?
After removal of the bladder the urine must be diverted. The most common diversion is an ileal conduit, which involves taking a segment of bowel and attaching the ureters, the water pipes leading from the kidneys, to one end. The other end is brought to the skin as a stoma. A bag placed over the stoma collects the urine, and the patient empties this bag when it gets full.
An alternative to the ileal conduit is the neobladder. This operation involves taking a longer segment of bowel and fashioning it into a pouch, which is then attached to the ureters and to the urethra. The neobladder can be considered in motivated younger patients with good kidney, liver and bowel function, good hand-eye coordination, and no evidence of cancer in the urethra.
What alternatives are there to having the bladder removed?
Multimodality treatment involves the combination of TURBT, chemotherapy and radiotherapy. It can be considered in carefully selected patients with good bladder function and tumours that do not extend beyond the muscle wall, or patients who are poor candidates for radical surgery. However, cancer may recur in up to one third of patients using this approach.