Bladder cancer originates from tissues of urinary bladder. According to the US database, it is the 6th most common cancer. In the USA, approximetely 70.000 new cases are diagnosed annually and 15.000 patients die because of bladder cancer. The incidence gradually increases in time. New technologies and treatment modalities pave the way for overall better survival rates.
Knowledge about the function and structure of bladder will be helpful for understanding bladder cancer. Urinary bladder is located inside the bony pelvis and collects urine as a reservoir. Urine passes from the kidney to urinary bladder through ureters (channels connecting the kidney and urinary bladder). The urinary bladder keeps urine at low pressure to allow for voluntary voiding.
Urinary bladder exit is called urethra, a channel present both in male and female individuals. Urinary bladder is made up of 3 layers. The inner layer is epithelium ensuring direct contact with urine, the middle layer is a muscular layer with detrusor muscle fibers and enabling voiding through contraction and the outer layer is serosa forming the outer part of the bladder.
The most important risk factor is tobacco consumption. When tobacco is consumed, carcinogenic substances are inhaled and they pass from lungs to the vascular system, finally filtered by kidneys and reach the mucosa of the urinary bladder. Dyes, solvents and different chemicals are also responsible for the development of bladder cancer. As carcinogenic chemicals directly contact with the bladder epithelium, 90% of bladder cancers originate there.
The typical sign is painless hematuria with or without clot (blood in urine). Sometimes, hematuria may be microscopic and cannot be seen with the naked eye. Microscopic hematuria needs to be evaluated in order not to misdiagnose any bladder cancer. Frequency and dysuria might also be the symptoms of bladder cancer.
It is mandatory for specialists to have a detailed history including tobacco consumption and physical examination. Ultrasonography or computed tomography may be used for visualising the urinary tract. The most valuable diagnostic tool is ‘’cystoscopy’’, which enables the visualization of the inner bladder through urethra by using a camera. Urine cytology is also helpful for flat tumors which may not be detected with the naked eye. After the diagnosis of bladder cancer, it is mandatory to scan the whole body with different radiological techniques.
Patients diagnosed with bladder cancer are examined cystoscopically and transurethral tumor resection (TUR) is performed. This procedure is totally endoscopic without any incision to the body. Pathologic specimen is examined by pathologists. This will identify the tumor depth and its histopathological subtype.
Before making any decision on the treatment plan, the tumor location, its pathological grade, the presence of perivesical invasion, the patient age and other comorbidites should be evaluated.
Most bladder cancers are limited to the inner epithelial layer without muscular layer involvement at the time of diagnosis. Those are called the superficial tumors of bladder. High-grade superficial tumors require additional intravesical immune therapies such as BCG (tuberculosis vaccine) or chemotherapy. Intravesical BCG treatment will trigger immunity against tumor cells. With regards to recurrence, periodical cystoscopy and imaging studies are needed in terms of follow-up.
Muscle-invasive bladder tumors require the total removal of bladder called ‘’radical cystectomy’’ in the literature. Almost all male patients are subject to prostatectomy and all female individuals to hysterectomy as well. Different techniques are used to form an artificial urinary bladder by the use of a segment of small intestines, mainly the ileum. This may be both connected to native urethra or to anterior abdominal wall as classical radical cystectomy is performed via open surgery. However, “Robotic Surgery” may also be used as a minimally invasive technique.
If bladder cancer involves outer layer (serosa) and adjacent organs, surgery is considered unsuitable for treatment. Systemic chemotherapy or radiotherapy may constitute the choices of treatment.