In Australia, we diagnose over 2800 new cases of bladder cancer each year. It can occur at any age, although the majority of cases are diagnosed after the age of fifty.
The most common type of bladder cancer arises from the innermost lining of cells, called urothelial cells. These comprise more than 90% of bladder cancer cases. Less common but more aggressive types of bladder cancer include squamous and adenocarcinoma, which arise from different cell populations.
What causes 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 irritation to the bladder can also develop 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 urinary tract infections. These patients tend to develop squamous rather than urothelial carcinoma.
Exposure to certain chemicals and dyes increases the risk of bladder cancer. Occupations with an increased risk 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 cancer after several years.
How do we diagnose bladder cancer?
Bladder cancer patients usually present with blood in the urine. They either see the blood directly, or their doctor detects it after sending the urine for microscopic examination. 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 undergo imaging of the kidneys and ureters, either with CT intravenous pyelogram or renal ultrasound. They also require a cystoscopy, a procedure that involves passing a small telescope into the bladder via the urethra to directly examine the inner lining of the bladder.
How do we treat bladder cancer?
Cancer treatment depends on the grade and stage. Grade describes tumour aggressiveness, and stage describes how far cancer has spread within and beyond the bladder. These factors determine the likelihood of cancer returning after it has been removed, and also the likelihood of it spreading to other parts of the body.
To work out grade and stage, a patient first needs a transurethral resection of bladder tumour (TURBT). This operation involves piecemeal removal of the tumour using special instruments via a cystoscope.
Low grade, low stage tumours require repeat cystoscopies over an extended period of time to check for recurrences. Additionally, patients with low stage but higher-grade tumours may require installation of immune therapy or chemotherapy into the bladder. If cancer has invaded 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, patients undergo a course of chemotherapy prior to removal of the bladder, with the goal of destroying microscopic foci of cancer outside the surgical excision field.
Multimodality treatment involves the combination of TURBT, chemotherapy and radiotherapy. It can be considered in carefully-selected patients who are poor candidates for radical surgery. However, cancer may recur in up to one-third of patients using this approach.
Where does the urine go after bladder removal?
The most common urinary diversion is an ileal conduit. This involves taking a segment of the small 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.
The neobladder is an alternative to the ileal conduit suitable in motivated younger patients with good kidney and liver function. This operation involves taking a longer segment of bowel and fashioning it into a pouch, then attaching this to the ureters and to the urethra.
Cancer that has spread into the muscle layer of the bladder wall requires aggressive treatment, either with cystectomy and chemotherapy or multimodality treatment.