Understanding genetic changes in bladder cancer

During the past decade scientists have made great progress in learning about the differences between normal cells and cancer cells. They are also finding out how these differences cause cells to grow too much and spread to other parts of the body. Several changes in the DNA (genetic material) of bladder cancers have been found. These findings have helped us understand more about this disease. The purpose of these studies is to decide if tests to identify these DNA abnormalities are useful in finding bladder cancers that recur (come back) after treatment. Other studies are being done to decide if tests to find these DNA abnormalities can help predict the prognosis (outlook) of bladder cancer patients and if this information is useful in choosing treatment.

Prevention

Patients who have had one bladder cancer that has been successfully treated are at risk for developing a new cancer in the urinary tract (including the bladder, lining of the kidneys, ureters, and urethra). Studies to see if certain vitamins or minerals could reduce the risk of a second cancer are going on now. Another study is looking at the effect of the nonsteroidal anti-inflammatory drug celecoxib (Celebrex) on that risk. Researchers are also looking for a vaccine to help lower the risk of a second cancer.

Photodynamic therapy

Photodynamic therapy (PDT) is a new method that may be useful in treating early stages of bladder cancer. Its usefulness is still being studied. PDT begins with the injection of a nontoxic chemical into the blood. This chemical is allowed to collect in the tumor for a few days. Then a special type of laser light is focused on the bladder through the cystoscope. The light changes the nontoxic chemical that has collected in the cancer cells into a new chemical that can kill them.

The advantage of PDT is that it can kill cancer cells with very little harm to normal cells. One drawback is that the chemical must be activated by light, so only cancers near the surface of the bladder, which can be reached by shining a special light through the cystoscope, can be treated in this way. This light cannot reach cancers that have spread deeper into the bladder wall or to other organs.

Side effects of PDT include redness or discoloration of the skin and sensitivity to the sun or to other light sources. These can last for up to 6 weeks after therapy and in some cases may be severe.

Chemotherapy

A number of chemotherapy drugs are being tested as treatment for bladder cancer. Some of these, such as irinotecan and oxaliplatin are already used to treat other types of cancer.

Anti-angiogenesis drugs

Anti-angiogenesis drugs (which kill cancers by stopping their blood supply) such as bevacizumab (Avastin) and sorafenib (Nexavar) have been effective against colorectal cancer and kidney cancer, and are currently being tested in patients with bladder cancer.

Targeted therapies

Researchers are learning more about the molecules within bladder cancer cells that control their growth and spread in order to develop new targeted therapies. Some of these drugs have been found to be useful in other cancers, such as lung cancer and colorectal cancer. Several clinical trials are testing targeted drugs such as lapatinib, erlotinib (Tarceva), trastuzumab (Herceptin), and gefitinib (Iressa) against bladder cancer.

Gene therapy

Gene therapy is another new method being tested for bladder cancer. One of these approaches uses special viruses that have been modified in the laboratory. The modified virus is injected into the bladder and infects the bladder cancer cells. When this infection occurs, the virus injects a gene into the cells for GM-CSF, an immune system hormone (cytokine) that may help activate immune system cells to attack the cancer.

Last Medical Review: 01/27/2009
Last Revised: 5/13/2009