2 The condition, current treatments and procedure
2.1 The most common form of bladder cancer is transitional cell carcinoma (TCC). Non-muscle-invasive TCC is classified as stage Ta when the tumour is confined to the urothelium with no spread into the wall of the bladder or beyond, and stage T1 when there is spread into the connective tissue layer between the urothelium and the muscle wall. It is graded from G1 (low grade, least aggressive) to G3 (high grade, most aggressive). Another type of non-muscle-invasive cancer is carcinoma in situ, in which aggressive cancer cells spread within the surface lining of the bladder.
2.2 Conventional treatment for non-muscle-invasive cancer is transurethral resection of bladder tumour (TURBT), in which malignant tissue is removed with an electrocautery device during cystoscopy. Intravesical chemotherapy with Bacillus Calmette-Guérin (BCG) vaccine or other chemotherapeutic drugs may also be used. The drug is instilled directly into the bladder, either alone or as adjuvant therapy after TURBT. The aim is to reduce the risk of cancer recurrence. Intravesical microwave hyperthermia may also be used, in combination with intravesical chemotherapy. Cystectomy may be needed in some patients.
2.3 Electrically stimulated intravesical chemotherapy (also known as electromotive drug administration) can be used as neoadjuvant treatment before TURBT, or as adjuvant treatment after TURBT. The procedure involves the use of a device to create an electric field across the bladder wall, with the aim of stimulating directional ionic and solute movement of the intravesical fluid. This increases absorption of the drug into the bladder lining.
2.4 The procedure is usually done using local anaesthesia. With the patient in a supine position, electrode pads are placed on the skin of the lower abdomen and a catheter (with an intravesical electrode) is inserted into the bladder through the urethra. When the catheter and electrodes are in place the chemotherapeutic drug solution (usually mitomycin C in saline or distilled water) is instilled into the bladder through the catheter. The cutaneous and intravesical electrodes are connected to a generator that creates a current of up to 25 milliamps. Treatment sessions last about 30 minutes and are repeated, often weekly, for 4 to 8 weeks or longer for adjuvant treatment. After the procedure, the bladder is drained and the catheter is removed.