Understanding genetic changes in bladder cancer
Scientists have made great progress in learning about the differences between normal cells and bladder cancer cells. They are also learning how these differences help cancer cells grow too much and spread to other parts of the body.
Researchers are now trying to determine if tests that identify genetic changes in bladder cancer cells can help predict a person’s prognosis (outlook), which might affect treatment, or if they are useful in finding bladder cancers that recur (come back) after treatment.
Researchers also hope to use this knowledge to develop new ways to treat bladder cancer.
Urine tests to look for bladder cancer
Several newer tests look for substances in urine that might help show if 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 urine. Telomerase is an enzyme that is often found in abnormal amounts in cancer cells. Early results with this test have been promising, and more studies are now being done.
Reducing the risk of bladder cancer coming back
A major concern for people who have had bladder cancer is that they have a high risk of developing a new cancer in the 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 foods, vitamins (such as vitamin E), minerals (such as selenium), dietary supplements (such as green tea extract or broccoli sprout extract), chemotherapy drugs, or other drugs can reduce the risk of the cancer coming back or developing a second bladder cancer. Researchers are also studying if newer types of 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 use against bladder cancer.
Some surgeons are using a newer approach to cystectomy in which they sit at a control panel in the operating room and maneuver robotic arms to do the surgery. This approach, known as a robotic cystectomy, lets the surgeon operate through several small incisions instead of one large one. This may help patients recover more quickly from surgery. This type of surgery is already used to treat some other cancers, such as prostate cancer, but it’s not yet clear if it’s as good as standard surgery for removing the bladder. This approach is being studied to see if this is the case.
Researchers are looking at a number of new medicines to see if putting them into the bladder after surgery can help lower the risk of the cancer coming back. The hope is to find some that are better and/or safer than currently used drugs such as BCG and mitomycin.
Photodynamic therapy (PDT) is now being studied to see if it’s useful in treating early stage bladder cancers. A light-sensitive drug is injected into the blood and allowed to collect in the cancer 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.
An 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. The light can’t reach cancers that have grown deeper into the bladder wall or have spread to other organs.
A major side effect of PDT is an intense sensitivity to the sun that can last for a few weeks after therapy. Even small amounts of sunlight can cause severe burns in a short time, so it’s very important to take precautions while getting this treatment.
You can read more about this kind of treatment in Photodynamic Therapy.
Immunotherapy is treatment that uses the body’s own immune system to fight the cancer.
Intravesical immunotherapy: One form of immunotherapy already used to treat some early bladder cancers is BCG, which is a type of intravesical therapy. When this germ is put into the bladder (in liquid form), it attracts immune cells to the bladder lining, which then attack cancer cells.
Immune checkpoint inhibitors: An important part of the immune system is its ability to keep itself from attacking the body’s normal cells. It does this by using “checkpoints” – molecules on immune cells that need to be turned on (or off) to start an immune response. Cancer cells sometimes use these checkpoints to avoid being attacked by the immune system.
Newer drugs that target checkpoint molecules such as PD-1 and PD-L1 hold a lot of promise as bladder cancer treatments. For example, atezolizumab (Tencetriq), which targets PD-L1, is now approved to treat advanced bladder cancer. Another checkpoint inhibitor, pembrolizumab (Keytruda), which targets PD-1, has also been shown to shrink some advanced bladder cancers in early studies.
Several other types of immunotherapy are now being studied as well.
As researchers have learned more about some of the changes in bladder cells that cause them to become cancer, they have begun to develop drugs that target these changes. These new targeted drugs work differently from standard chemo drugs. They may work in some cases when chemo drugs don’t, and they tend to have different (and often less severe) side effects.
Many targeted drugs are already used to treat other types of cancer. Some of these drugs are now being studied for use against bladder cancer as well, including lapatinib (Tykerb) and erlotinib (Tarceva).
Other drugs target the blood vessels that allow tumors to grow. These are known as anti-angiogenesis drugs. Examples include bevacizumab (Avastin), sorafenib (Nexavar), cabozantinib (Cometriq), and pazopanib (Votrient), which are already used for some other types of cancer. They are now being studied for use against bladder cancer, usually combined with chemotherapy.
Many other new targeted drugs are being studied in clinical trials as well.
Gene therapy – adding or changing the actual genes inside cancer cells or other cells in the body – is another new treatment method being tested for bladder cancer. One approach to gene therapy uses special viruses that have been modified in the lab. The modified virus is put 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 that can help immune system cells to attack the cancer. This and other approaches to gene therapy are still in the early stages of development.
Last Revised: 05/23/2016