Understanding genetic changes in bladder cancer
During the past few decades 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. Researchers are now trying to determine if tests that identify these DNA changes can help predict the prognosis (outlook) of bladder cancer patients (which might affect treatment) or if they are useful in finding bladder cancers that recur (come back) after treatment.
Urine tests to look for bladder cancer
Several newer tests look for substances in the urine that might indicate a person has bladder cancer. These tests are used mainly to help diagnose bladder cancer or to look for recurrence in people who have already been treated. Researchers are now looking to see if these tests might be helpful even earlier, to screen for bladder cancer in people without symptoms (see "Can bladder cancer be found early?").
One new test looks for a substance called telomerase in the urine. Telomerase is an enzyme that is found often in cancer cells. Early results with this test have been promising, and more studies are now under way.
Reducing the risk of bladder cancer recurrence
A major concern in people who have had bladder cancer is that they are at risk for developing a new cancer in bladder or other parts of the urinary tract (including the lining of the kidneys, ureters, and urethra).
Studies are now looking to see if certain vitamins (such as vitamin E), minerals (such as selenium), dietary supplements (such as green tea extract and broccoli sprout extract), chemotherapy drugs, or other drugs can reduce the risk of a second bladder cancer. Researchers are also looking to see if vaccines can boost the body's immune system and help lower the risk of a second cancer.
Bladder cancer treatment
Several newer types of treatment are now being studied for used against bladder cancer.
Photodynamic therapy
Photodynamic therapy (PDT) is a newer treatment method that may be useful in treating early stage bladder cancers. Its usefulness is still being studied.
For this treatment, a special light-sensitive drug is injected into the blood and allowed to collect in the tumor cells for a few days. Then a special type of laser light is focused on the inner lining of the bladder through a cystoscope. The light changes the drug 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 nearby normal cells. One drawback is that the chemical must be activated by light, so only cancers near the surface of the bladder lining can be treated in this way. This light cannot reach cancers that have grown deeper into the bladder wall or have spread to other organs.
The main side effect of PDT is an intense sensitivity to the sun that can last for several weeks after therapy. Even small amounts of sunlight can cause severe burns in a short time, so it is very important to take precautions while getting this treatment.
Targeted therapies
As researchers have learned more about some of the changes in bladder cells that cause them to become cancerous, they have begun to develop drugs that target these changes. These new targeted drugs work differently than standard chemo drugs. They tend to have different (and often less severe) side effects.
Many targeted drugs are already in use to treat other types of cancer. Some of these drugs are now being studied for use against bladder cancer as well, including sunitinib (Sutent®), lapatinib (Tykerb®), erlotinib (Tarceva®), trastuzumab (Herceptin®), and gefitinib (Iressa®).
Other drugs target the blood vessels that allow tumors to grow. These are known as anti-angiogenesis drugs. Examples include bevacizumab (Avastin®) and sorafenib (Nexavar®), which are already used for some other types of cancer. They are now being studied for use against bladder cancer, usually combined with chemotherapy.
Gene therapy
Gene therapy – adding or changing the actual genes inside cancer cells or other cells in the body – is another new method being tested for bladder cancer. One of these approaches uses special viruses that have been modified in the lab. 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. This and other approaches to gene therapy are still in the early stages of development.
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