Contents
Introduction
Epidemiology
- Uncommon before the age of 40, only 5% of cases present before the age of 60.
- Male to female ratio 4:1
- Incidence is about 32 per 100 000 in men, and 10 per 100 000 in women.
- Bladder tumours are by far the most common – 50x as common as tumours in any other region of the UT.
- Peak age of presentation is 65-69 in men and 75-79 in women.
- The incidence is declining thanks to the improvement of working conditions and supervision of workers is vulnerable occupations in the last 50 years. It is also expected that incidence will decline in the future in the West, due to changes in attitudes to smoking.
Aetiology
Smoking – it is thought that this accounts for 40% of cases of bladder cancer
Exposure to industrial chemical carcinogens; such as β-naphthylaminen and benzidine – these are found in:
- Chemical, cable, rubber, leather, painting and dye industries.
- Herbal weight loss preparations
- It is thought that environmental exposure to these chemicals is responsible for about 25% of cases of TCC, however, in the UK, only 5% of people with TCC are eligible for compensation (‘prescribed disease benefit’).
Exposure to certain drugs; phenacetin, cyclophosphamide
Chronic inflammation
Clinical features
- Painless haematuria is by far the most common presentation. In some cases, pain may occur due to clot retention.
- There may be symptoms suggestive of a UTI, but urine will be negative for bacteria.
- There may be pain from local nerve involvement in the cancer.
- TCC of the kidney and ureter may give rise to flank pain (and haematuria) as a result of urinary tract obstruction.
Investigations
- USS and CT
- Analysis of urine for malignant cells.
- Cystoscopy is also usually carried out, unless there is evidence that the malignancy is in the upper UT.
- In men under 20 and women under 30, if the haematuria is present with bacteria, then TCC can be omitted as a possible differential diagnosis as long as the haematuria disappears with treatment.
Treatment
Staging is again by the TNM system. However, there is one exception. Usually tumours that do not invade the basement membrane as described as benign, and thus not included in the TNM system. However for bladder tumours, they are classed as malignant (because 70%* of them will progress to malignant disease if untreated). They are classed as Ta (as opposed to T1-T4) tumours.
- * -the other 30% are papillomas.
Pelvic and ureteric tumours – are treated by nephroureterectomy. Radio and chemotherapies have been shown to be of little value. There should be follow up cystoscopy at regular intervals because 50% of these patients will develop subsequent bladder tumours.
Bladder tumours – treatment for these depends on the stage (described above):
- pTa stage – these are treated by transurethral resection. Again, cystoscopy at regular intervals is necessary, as 70% will reccur
- pT1 stage – these tumours have already shown their invasive potential – and they are treated in an unusual manner:
- Intravesical BCG – this is the vaccine that is given foe TB. It stands for Bacillus Calmette-Guerin. It is given in bladder cancer as a form of immunotherapy. The mechanism is unclear, but giving this vaccine in this way initiates an immune response against the tumour. It is usually given after the main tumour has been removed by surgery. The vaccine is left in place in the bladder for 2 hours. Even with this treatment, 50% of patients will develop invasive disease within 5 years.
- pT2 stage and above – this is tumours that have invaded the muscle layers of the bladder or further. In patients under 70, treatment is with radical cystectomy. In patients over 70, treatment is with radiotherapy. Cystectomy carries a mortality risk of 2-4% which obviously rises with age. Both treatments have their downsides:
- Cystectomy – you still need to replace the bladder somehow – often with a piece of bowel. This can lead to problems absorbing certain things from the diet, and may also cause diarrhoea. There may also be metabolic problems as a result of electrolyte imbalance that results from the absorptive capacity of the gut mucosa when placed in a urinary environment. In some cases, this new bladder can be joined to the urethra, but in other an ileal conduit and permanent stoma may be formed.
- Radiotherapy – only ever recommended in older patients, it causes proctitis in 10% of patients.
Prognosis
5 year survival rates:
- 80-90% for lesions not involving the bladder muscle
- 5% for those with metastatic disease