Intravesical microwave hyperthermia and chemotherapy for non-muscle-invasive bladder cancer

Evidence-based recommendations on intravesical microwave hyperthermia and chemotherapy for non-muscle-invasive bladder cancer in adults. This involves using microwaves to improve the effect of the chemotherapy given directly into the bladder.

# Recommendations
The evidence on the safety of intravesical microwave hyperthermia and chemotherapy for non-muscle-invasive bladder cancer shows there are well-recognised adverse events. Current evidence on its efficacy is limited in quality. Therefore, this procedure should only be used with special arrangements for clinical governance, consent, and audit or research. Find out what special arrangements mean on the NICE interventional procedures guidance page.
Clinicians wishing to do intravesical microwave hyperthermia and chemotherapy for non-muscle-invasive bladder cancer should:
Inform the clinical governance leads in their NHS trusts.
Ensure that patients and their carers understand the uncertainty about the procedure's safety and efficacy, alternative treatments and provide them with clear written information. In addition, the use of NICE's information for the public on intravesical microwave hyperthermia and chemotherapy is recommended.
Audit and review clinical outcomes of all patients having intravesical microwave hyperthermia and chemotherapy for non-muscle-invasive bladder cancer. NICE has identified relevant audit criteria and has developed NICE's interventional procedure outcomes audit tool (which is for use at local discretion).
Patient selection should be by a specialist bladder cancer multidisciplinary team. The procedure should only be done in specialist centres by clinicians who have had supervised training in the procedure.
NICE encourages further research into intravesical microwave hyperthermia and chemotherapy for non-muscle-invasive bladder cancer. Research should include randomised controlled trials, which stratify patients by risk and give adequate follow-up. They should report frequency of adverse events, patient-reported outcome measures, overall and disease-free survival and quality of life.
NICE may review this procedure on publication of further evidence.# The condition, current treatments and procedure

# The condition
Transitional cell carcinoma is the most common form of bladder cancer. Non-muscle-invasive transitional cell carcinoma is classified as stage Ta when the tumour is confined to the uroepithelium with no spread into the bladder wall or beyond. It is classified as stage T1 when there is spread into the connective tissue layer between the urothelium and the muscle wall. Non-muscle-invasive transitional cell carcinomas can be graded from G1 (low grade, least aggressive) to G3 (high grade, most aggressive). Carcinoma in situ is a form of tumour consisting of aggressive cancer cells which spread within the surface lining of the bladder.

# Current treatments
Surgical interventions for non-muscle-invasive transitional cell carcinoma include transurethral resection, in which malignant tissue is removed with an electrocautery device during cystoscopy. Bacillus Calmette-Guerin (BCG) vaccine or chemotherapy drugs may be put directly into the bladder, either as a treatment in itself, or as adjuvant therapy after transurethral resection. Cystectomy may also be necessary in some patients.

# The procedure
Intravesical microwave hyperthermia and chemotherapy can be used as neoadjuvant therapy before transurethral resection, with the aim of eradicating tumours. Alternatively the procedure can be used after transurethral resection, as adjuvant therapy (sometimes referred to as prophylactic treatment), aiming to prevent recurrence. Hyperthermia is believed to have a direct and immune-mediated cytotoxic effect on tumour cells and to improve the efficacy of chemotherapy drugs.
The procedure can be done on an outpatient basis. Using local anaesthetic urethral gel, a balloon catheter (containing a radiofrequency antenna and several insulated thermocouples), is inserted through the urethra into the bladder. Ultrasound is sometimes used to assess the position of the device. The radiofrequency antenna gives off microwaves which heat the superficial layers of the bladder wall. The thermocouples are spread out from the catheter and pushed against the bladder lining. They monitor temperature to help prevent overheating. A solution of a cytostatic agent, usually mitomycin C, is instilled into the bladder, between the bladder wall and the balloon surface. The solution is continuously pumped out of the bladder, cooled, and recirculated to prevent overheating. Treatment sessions typically last between 40 minutes and 60 minutes and are usually repeated weekly for 4 to 8 weeks, or longer for adjuvant treatment.