Bladder Cancer

The urinary bladder is the organ situated at the lower part of the abdomen (figure 1) which stores urine till it is voided. In Singapore and Malaysia, bladder cancer used to be the most common cancer of the urinary tract in both males and females. Males are affected 2 to 3 times more commonly than women. In recent years, as increasing numbers of cancer of the prostate are diagnosed, bladder cancers may now only be equal to prostate cancers in terms of incidence. However in the U.S., prostate cancer incidence is approximately 5 to 6 times that of bladder cancer.

Causes
Several chemical agents are incriminated in the causation of bladder cancers. Cigarette smoking is one well established risk factor. The more one smokes the greater the risk of bladder cancer. Other chemicals linked to bladder cancers are grouped as aromatic amines (beta-nephthylamines, xenylamine, benzidine). These are associated with the textile, leather, rubber, dye, paint, hairdressing and organic chemical industries. Long term exposure is necessary. In the middle east (Egypt), a parasitic infestation of the bladder - schistosomiasis is associated with bladder cancer. This parasite is not found in Malaysia.

Symptoms
The most common presentation is blood in the urine (haematuria) (Figure 2). Usually, this is painless and the blood may be visible to the naked eye (gross haematuria) or can only be seen under the microscope (microscopic haematuria). Sometimes patients present with irritative bladder symptoms like frequency of urination or pain sensation at the lower part of the abdomen. Quite commonly, the diagnosis of bladder cancer is delayed because haematuria is intermittent or attributed to other causes - most commonly urinary tract infection. Therefore a high index of suspicion is necessary by the doctor whom patient consults.

Diagnosis (Investigations)
Since haematuria could arise from the entire urinary tract (kidney, ureter and bladder), the entire urinary tract needs to be evaluated for possible causes. The best initial investigation is a radiological test called an Intravenous Venogram (IVU). (Figure 3). It involves the injection of contrast material intravenously which is then filtered by the kidney thereby outlining the urinary tract. A bladder tumour may show as a filling defect if the tumour is large enough. Sometimes, an office ultrasound examination may also show the presence of a tumour lesion in the bladder. A negative IVU or Ultrasound examination does not rule out bladder cancer as subtle abnormalities or small lesions may not show.

A cystoscopy (looking into the bladder via the urine passage with a telescopic instrument) is mandatory for haematuria especially if the IVU or ultrasound is normal. Cystoscopy can be carried out under local anaesthesia as an outpatinet procedure with a flexible instrument without discomfort to the patient. The patient can even witness the event when the urologist uses video-camera equipment. The diagnosis of bladder cancer can then be confidently made and further preliminary elective management planned and discussed with the patient.

Management (Treatment)
Once the diagnosis of a bladder lesion is confirmed, the patient is arranged to be taken to the operating room. General or epidural anesthesia is usually given. The urologist will look in the bladder with a rigid cystoscope and the tumour size, location within the bladder, number of tumours and characteristics are recorded. Thereafter, the tumour/s are removed with an instrument called a resectoscope. Specimens which are removed are sent to the pathologist for interpretation as to the grade of tumour and the depth of invasion. Biopsies of normal looking bladder are also done so as not to miss tumours (Carcinoma in situ) not visible to the urologist’s eyes. Very important information are obtained by this manner of initial endoscopic evaluation and management and form the basis for clinical staging of the patient’s disease.

At the time of diagnosis, 80% of bladder tumours are superficial, i.e,insert. confined to the bladder (urothelium). The other 20% are invasive disease (extended into the layer of the bladder beneath the lining). Invasive tumours can associated with metastatic spread to the lymph nodes or distant organs such as the lungs, bones and liver. Superficial tumours carry a good prognosis but do tend to recur frequently and may have a risk to becoming invasive in the future especially if the pathological grade of the tumour is of the aggressive type or if carcinoma in situ is present. Prognosis for invasive disease is guarded if not treated appropriately.

After the initial endoscopic tumour resection of superficial bladder tumours, the patient is placed on a program of periodic surveillancecystoscopies ranging from 3-monthly to yearly depending on the behaviour of the tumours. High risks patients-multiple tumours, high grade tumours and those associated with carcinoma in situ can be treated additionally with a choice of several anticancer agents instilled into the bladder (intravesical therapy) to prevent recurrence. A typical treatment protocol would consist of weekly instillation for 6 weeks. Common agents used are Mitomycin, BCG and Adriamycin.

Treatment of patients with invasive bladder cancer has to be individualised according to the general status of health, extent of cancer and personal preferences after explanations by the urologist concerning the various options available.

Complete surgical removal of the bladder (radical cystectomy) (figure 4) for muscle invasive cancer of the bladder provides the best chance of cure. Partial cystectomy is seldom done as most bladder tumours are of the transitional cell type and disease may recur in the remaining bladder. When a radical cystectomy type of operation is done, a procedure to divert the urine from the kidneys and ureters into a small segment of small bowel fashioned as an ileal conduit to appear as a stoma on the abdominal wall is necessary. Urine is drained into an external collection bag - urostomy appliance. This type of diversion remains the most popular as it is relatively easier and quicker to construct and with low complication rates. Nowadays, it is possible to construct a continent type of urinary reservoir again using bowel.

A Continent reservoir has a smaller stomal opening at the abdominal wall. The patient does not need to wear an external appliance but empties the reservoir by self intermittent catheterisation 4-6 times a day using a catheter through the stoma. Such types of operations are more difficult and longer to perform. Motivated and younger patients are the more suitable candidates for these procedures.

In suitable patients, a new bladder can be reconstructed from bowel and reconnected to the native urethra in order that the patient can avoid normally. These operations are complex and only some patients are suitable and fit enough to undergo them.

Patients who are not suitable, unfit or refuse to accept cystectomy can be offered radiotherapy. Although radiotherapy allows bladder conservation, the 5 year survival for patients with deeper muscle invasion is only 20%-40%.

Metastatic bladder cancer: Patients with gross regional lymph nodes spread or distant organs spread do not do well normally. Systemic Chemotherapy can be given using quite combination anticancer drugs like Methotrexate, Vinblastine, Adriamycin, Cisplatinum or Paclitaxel.


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