Bladder instillation therapy is a therapeutic procedure that can be used to treat non-muscle-invasive bladder cancer (urinary bladder cancer), among other conditions. In tumor therapy, instillation therapy is usually used as an adjuvant therapy (supplementary or supportive therapy measure). The use of the respective drugs depends on the study results for the disease at hand. Since approximately 50% of all patients with non-muscle-invasive bladder cancer experience at least one tumor recurrence within one year, bladder instillation therapy is started two weeks after complete TUR (transurethral resection (of the prostate); surgical technique in which diseased tissue is removed from the urinary bladder or prostate) when therapy is recommended. The urinary bladder is an ideal organ for local therapy. Bladder instillation therapy represents a very successful therapeutic procedure.
Indications (areas of application)
Tumor therapy
- Noninvasive urothelial carcinoma of the urinary bladder – within the framework of evidence-based therapeutic measures, bladder instillation therapy is used to treat carcinoma in situ (literally, “cancer in situ”; early stage of an epithelial tumor without invasive tumor growth), pTa low-grade tumor, pTa high-grade tumor, and pT1 tumor (therapy of different tumor stages). Therapeutic substances used for intravesical (in the urinary bladder) chemotherapy include mitomycin C, doxorubicin, epirubicin. BCG (Bacillus Calmette-Guérin) is used for intravesical immunotherapy. BCG is an attenuated tuberculosis pathogen. With the help of the pathogens, an inflammatory reaction can be induced in the urinary bladder, through which the tumor cells can be killed. The success of therapy should be assessed several times by cytological examination of exfoliated urinary bladder cells (exfoliative cytology) from the urine.
Cystitis therapy
- Interstitial cystitis – Analogous to bladder instillation therapy, the procedure is also used for inflammatory processes of the urinary bladder, as it allows a high local concentration of effect with a low systemic side effect. The following drugs are used: Sodium pentosan polysulfate, heparin, dimethyl sulfoxide (DMSO), Bacillus Calmette-Guérin, hyaluronic acid and chondroitin sulfate. Furthermore, there is the possibility of hydrodistension of the urinary bladder (overdistension of the urinary bladder by means of water), in which sterile saline is applied as intravesical therapy. In addition to treatment, hydrotension is also used for diagnosis of interstitial cystitis (cystoscopy in hydrotension).
Contraindications
- Bladder wall perforation – Perforation would result in leakage of the chemotherapeutic agent into various body cavities, which would be a life-threatening condition.
- Cystitis (in tumor therapy) – If inflammation of the urinary bladder is present, it must be treated separately before therapy.
- Clear macrohematuria – If there is visible excretion of blood in the urine, this is a contraindication.
- Active tuberculosis in BCG therapy – If active tuberculosis is known, it must be treated, if possible, so that BCG therapy can be given subsequently. However, the use of other drugs for bladder instillation therapy is usually more appropriate. If a patient has a positive tuberculin test (search test for tuberculosis), active tuberculosis must be excluded diagnostically.
Before therapy
- Medication history-To avoid possible reduction in efficacy of bladder instillation therapy, in particular, the use of medications for tuberculosis treatment should be inquired about. Examples would include ethambutol, INH (isonicotinic acid hydrazide), and rifampicin. Antibiotics such as fluoroquinolones, but also lubricants can cause a worsening of the effect of tumor therapy.
- Fluid abstinence – No fluids should be ingested four hours before the procedure is performed. In addition, bladder emptying is mandatory before therapy.
- Urinary alkalinization – Urinary alkalinization (urine deacidification) with sodium bicarbonate is necessary during therapy with mitomycin C, among others.
- Urine examination – Before each therapy implementation, the urine is examined for abnormalities by means of urine sticks (rapid test).
The procedure
Currently, there is no standardized application regimen for chemotherapeutic agents to perform bladder instillation therapy. The drug is applied along with 30-50 ml of solvent, such as saline, via a disposable catheter with intravesical residence time (time spent in the urinary bladder) of a few hours, depending on the drug administered. Therapy is typically initiated with an induction cycle that involves application of the chemotherapeutic agent 4-8 times per week. Thereafter, maintenance doses are usually administered once a month. The fixed intervals can reduce side effects while not significantly increasing the risk of loss of efficacy of the chemotherapeutic agent.
After therapy
Following the procedure, increased fluid intake should be maintained for two days to remove toxic (poisonous) substances from the bladder and thus reduce side effects. In addition, follow-up examinations are essential to assess progression (progression of the disease), among other things.
Potential complications
The incidence of complications varies depending on the drug used, among other factors.
- Cystitis (bladder infection) – Application of the chemotherapeutic drug significantly increases the risk of developing cystitis, because there is not complete selectivity of the drug against cancer cells (healthy cells are also attacked).
- Irritation of bladder emptying – Due to the damage to the bladder, bladder emptying disorders occur relatively often, but they do not have to become chronic.
- Hematuria – As a result of therapy, macroscopic (visible to the naked eye: macrohematuria) or microscopic blood discharge through the urine (microhematuria) may occur.
- Allergy – Allergic reactions may occur towards the substance used.
- Nausea – In the course of therapy, there may be a feeling of nausea, which can be treated with medication.
- Fever – Increased body temperature may occur as a result of the immune response.
- Necrotizing cystitis – A rare but life-threatening consequence of therapy is this form of cystitis with damage to the bladder tissue.
- Stenosis of the urinary tract – The damage and the evocation of an inflammatory reaction can permanently narrow the urinary tract.
- Bladder volume reduction – Due to a reduction in bladder volume, a frequent urge to urinate is felt.