- Painless bloody urine is the hallmark of bladder cancer.
- Most bladder cancers are superficial type, which can be resected completely.
- Bladder cancers are prone to recurrences, hence the need for additional chemotherapy or BCG delivered into the bladder after the tumour has been resected.
- Once the cancer has invaded into the bladder muscle, the whole bladder has to be removed.
- Should the cancer spread to the lymph nodes, cure is not possible and only chemotherapy can control the disease.
Bladder cancer is now the 7th most common cancer in Singapore. Men are affected 3 times more commonly than women and it occurs mostly in those above 50 years old. The causes for bladder cancer are ageing, chemical agents and cigarette smoking.
The most common presentation is painless gross haematuria (blood in the urine) [Fig 1]. It can also present with irritative bladder symptoms, eg. frequency and urgency of urination. Quite commonly, the diagnosis is delayed because the haematuria is intermittent or wrongly attributed to other causes esp. urine infection.
Although the urine can be sent for cytologic examination to look for presence of cancer cells, its accuracy is limited by low sensitivity (< 50% pick-up rate) [Fig 2]. Hence, the result is not to be relied on when deciding whether a patient does or does not have cancer.
Since haematuria can arise from any part of the urinary tract, the standard initial investigation is an xray called Intravenous Urogram (IVU). It involves the injection of contrast material which is excreted by the kidneys to outline the urinary tract. A bladder tumour may show up as a ‘filling defect’ if the tumour is large enough [Fig 3].
Increasingly, CT scan is being used because it is more sensitive and can reveal even small tumours along the urinary tract [Fig 4]. It also gives additional information as to whether the cancer has spread to the lymph nodes and beyond. However, the radiation exposure is higher and it costs more.
Sometimes, the bladder tumour can also be seen on an ultrasound examination if it is > 1 cm [Fig 5].
A negative xray scan or ultrasound does not rule out bladder cancer as small tumours < 1 cm may not be obvious. As such, cystoscopy is mandatory even if the scan is reported to be “normal”.
This is easily done under local anaesthesia in the clinic using a flexible scope without causing much discomfort [Fig 6]. The advantage is that even small tumours can be seen and biopsy taken to confirm if the bladder tumour is indeed cancerous as some 5% of bladder tumours may in fact be benign.
i) Early (superficial) Stage
Once the diagnosis of a bladder lesion is made, endoscopic surgery using a resectoscope to cut away the tumour (called TURBT) is the standard surgery [Fig 7]. Biopsies of normal looking bladder are also taken so as not to miss pre-cancerous tumours of the bladder lining (carcinoma-in-situ or CIS). After the tumour is removed, separate muscle biopsies are taken and the bladder is palpated with both hands. General anesthesia is usually preferred as it may take up to 1 hour to resect a large tumour.
From the pathology report, the cancer is staged according to its grade and the depth of invasion [Fig 8].
At the time of diagnosis, 80% of bladder tumours are superficial, i.e. confined to the bladder lining. The other 20% are invasive (i.e. penetrated the muscle layer of the bladder). Superficial tumours carry a good prognosis but have a tendency to recur. If so, they have the real risk of becoming invasive in the future, especially if the grade is high-grade or if CIS is present. Invasive tumours will eventually spread to the lymph nodes and distant organs. Prognosis for invasive disease is poor, hence it is important to treat bladder cancer at its early stage (stage 1) before it invades the muscle layer.
Even if the histology confirms the tumour is of superficial stage, periodic surveillance cystoscopies are mandatory to pick up possible early recurrences. The regime is 3-monthly for the first year, then 6-monthly to yearly depending on the behaviour / frequency of recurrence. It is important to note that bladder cancers may look the same but may not behave the same.
b) Intravesical Chemotherapy
Those at high risk of recurrence, eg. large or multiple tumours, high-grade type and presence of CIS disease require cytotoxic agents (Mitomycin C) or immune-enhancing agent (BCG) instilled into the bladder to reduce the risk of recurrence [Fig 9]. A typical treatment protocol would consist of weekly instillation for 6 weeks followed by a weekly booster over 3 weeks in high-risk cases. BCG is preferred for high-grade cancers, recurrent cancers and those with CIS disease.
ii) Advanced (Invasive) Stage
Treatment of patients with invasive bladder cancer has to be individualised according to the general fitness and extent of cancer. Total removal of the bladder (radical cystectomy) for muscle-invasive cancer (Stage 2 and 3) gives the best chance of cure. Superficial, high-grade cancers with CIS that frequently recur are also candidates for total cystectomy. Partial cystectomy is not advisable as most bladder tumours are of the transitional cell type and can recur in the remaining bladder. After a radical cystectomy, the urine from the kidneys and ureters is diverted into a short segment of small bowel (called an ileal conduit) which opens as a stoma on the abdominal wall [Fig 10]. Urine is collected in an external collection bag (urostomy). This type of diversion remains the most popular choice as it is relatively easy and quick to construct. For younger patients, and those who wish to remain continent or avoid a urostomy, a â€œnew bladderâ€ can be constructed using small intestine. This neobladder is reconnected to the native urethra so that the patient can void normally. Although there is no need to wear an external bag, self intermittent catheterisation may still be needed as the neobladder may not empty well or become blocked with mucus produced by the intestine lining. Nocturnal incontinence (bed-wetting) is often a problem too. As a neobladder operation are more difficult and takes longer to perform, only motivated and fit, young patients are suitable candidates [Fig10].
Although radiotherapy is a safer option and allows bladder conservation, the 5-year survival for bladder cancer with muscle invasion is only 20% to 40%. The limitation with radiotherapy is that it may not kill the cancer cells completely and there will be cumulative side-effects on the bladder and bowel, leading to recurrent bleeds and incontinence. Also, the radiotherapy has to be delivered daily for a period of 6 weeks.
c) Systemic Chemotherapy
Once the cancer has spread to the lymph nodes, cure is not possible and only systemic chemotherapy is given to control the cancer. This is delivered by the medical oncologist.