Intravesical therapy is a treatment that is put directly into the bladder (through a catheter) rather than being given by mouth or injected into a vein. The most common intravesical therapy used in bladder cancer is Bacillus Calmette-Guerin (BCG). This treatment causes the body's own natural defenses (immune system) to attack the bladder cancer. Chemotherapy drugs can also be used in intravesical therapy.
 

Bacillus Calmette-Guerin therapy
 

Bacillus Calmette-Guerin (BCG) is considered the most effective intravesical immunotherapy for treating low-stage bladder cancer. BCG is a bacterium that is related to the germ that causes tuberculosis (TB). It is given as an injection in some areas of the world to protect people against TB infection. To treat bladder cancer, BCG is placed directly into the bladder through a catheter. The body's immune system responds to BCG. Immune system cells are attracted to the bladder and activated by BCG, which in turn affects the bladder cancer cells. It is usually given once a week for 6 weeks. Sometimes long-term maintenance BCG therapy is given. BCG therapy may be given along with a transurethral resection of the tumor.
 

Treatment with BCG may cause symptoms that are like having the flu, such as fever, chills, and fatigue. It can also cause a burning feeling in the bladder. Rarely, BCG can spread through the body, leading to a life-threatening infection. One sign of this can be a persistent high fever (greater than 101.5°) that does not get better when you take an analgesic (such as aspirin, ibuprofen, or acetominophen). In such cases, prompt medical care should be sought. These infections can be treated with the antibiotics used to treat TB.
 

Interferon
 

Interferons are substances that stimulate the immune system. They are naturally produced by several types of cells in the body, and are also made in the lab to use as medicine. Interferon-alpha is the type most often used to treat cancer. It can be helpful in the intravesical treatment of bladder cancer.
 

Possible side effects include muscle aches, bone pain, headaches, problems with thinking and concentration, fatigue, nausea, and vomiting. These problems are temporary and usually improve after treatment is completed. Other drugs may be given along with the interferon to lessen these side effects.
 

Intravesical chemotherapy
 

In intravesical chemotherapy, anticancer drugs are put into the bladder through a tube (called a urinary catheter). Medicines given this way reach cancer cells in the bladder lining without affecting cells elsewhere. Because it mainly affects the cells lining the bladder, any cancer outside of the bladder lining is not treated. Drugs given into the bladder can't reach cancer cells that have grown deeply into the bladder wall. They also can't reach cancer cells in the kidneys, ureters, and urethra, or those that have spread to other organs.
 

For this reason, intravesical chemotherapy is used only for noninvasive (stage 0) or minimally invasive (stage I) bladder cancers. This treatment uses drugs that kill actively growing cancer cells. Many of the same drugs are given systemically (by mouth or into a vein) to treat more advanced stages of bladder cancer.
 

Mitomycin and thiotepa are the drugs used most often for intravesical chemotherapy. Valrubicin was approved for this use about 10 years ago. Intravesical gemcitabine, taxotere and other agents in combination are also being studied. Delivery of mitomycin into the bladder along with heating the inside of the bladder, a treatment called electromotive mitomycin therapy is also being investigated.
 

One of the main advantages of giving chemotherapy into the bladder instead of as an injection into the bloodstream, is that the drugs are usually not absorbed. This allows you to avoid many of the unwanted side effects that can occur with systemic chemotherapy. An exception to this is the drug thiotepa, which is rarely absorbed from the bladder, causing toxicity in the rest of the body.
 

The main side effects of intravesical chemotherapy are irritation and a burning feeling in the bladder.