Genetic Testing and Bladder Cancer
- Cancer is caused by genetic mutations that change the way that cells function. Some of these mutations can be inherited, but many are also acquired over the course of a person’s lifetime. Genetic alterations can cause cells to divide rapidly and form a tumor.
- Doctors use genetic testing to analyze the genetic abnormalities present in different patients’ cancers, helping them to predict which treatment options might be most effective.
- In addition to environmental factors like smoking and chemical exposure, bladder cancer can be caused by inherited gene mutations including Birt-Hogg-Dubé syndrome, Cowden Syndrome and Lynch Syndrome.
Genetic testing helps identify specific genes that have mutated or been altered in a way that causes normal cells to become cancerous. These results are used by healthcare providers to predict responses to various types of treatment and monitor the progress of the disease. Genetic testing can refer to both germline testing (mutations in cells without cancer ) and also somatic testing of a patient’s tumor (mutations in cells with cancer).Read More
“What genetic testing means is understanding in a comprehensive way all the genetic abnormalities that may be present in one patient’s cancer that may not be present in others.”
When examining genetic changes within tumor cells, researchers look for two main things:
- Which genes have mutated
- If those mutations are in genes that are known to cause bladder cancer
These genetic abnormalities are what researchers are beginning to use as biomarkers for predicting patient responses to different forms of treatment.
The Role of Genetics and Family History
In some families, bladder cancer occurs at higher rates than in the general population. In these cases, careful examination of the genealogy may reveal specific mutations passed from parent to child that may lead a medical provider to suspect one of the hereditary forms of bladder cancer. Some germline mutations linked to bladder cancer include:
While it’s possible, inherited gene mutations aren’t as commonly associated with bladder cancer as they are with other types of cancer, such as breast and ovarian. Sometimes, bladder cancer may occur in families because of toxic chemical or environmental exposures.
There are certain factors that increase an individual’s risk for developing bladder cancer even if no family history exists. These include smoking and exposure to specific chemicals over long periods of time.
There are also inherited genetic syndromes that may place an individual at greater risk for developing bladder cancer. These include:
- Birt-Hogg-Dubé syndrome: A rare genetic disorder that makes individuals more susceptible to developing kidney cysts, spontaneous pneumothorax (collapsed lungs) and cancers of the skin, breast, and bladder.
- Cowden Syndrome: A genetic predisposition characterized by noncancerous growths called hamartomas and an increased risk for certain cancers, including bladder cancer.
- Lynch Syndrome: Also known as hereditary nonpolyposis colorectal cancer (HNPCC), this condition can lead to an increased risk of developing colon and bladder cancers, along with others.
The Role of Genetics in Bladder Cancer Treatment
If genetic testing reveals you lack certain genes mutated in bladder cancer, you may be less likely to respond to certain treatments. These include targeted therapies, immunotherapies and chemotherapy drugs.
Genetic testing is not the only factor that determines your response to certain treatments. Even if your bladder cancer has all the genetic mutations that predict response to certain treatments, it still may not respond to them, because genetics is only one factor in determining a treatment’s effectiveness.
To increase the likelihood of response, bladder cancer treatments need to be combined with interventions designed to help your immune system target and kill cancer cells.
Genetic testing may also inform some decisions you and your medical team make as part of your ongoing care. If you are planning additional treatment after surgery or radiation, genetic testing may help determine the most appropriate treatment to use.
Should I Have Genetic Testing Done for My Bladder Cancer?
Genetic testing may be beneficial for many people with cancer. However, no guidelines exist to determine who should get genetic testing and the type of testing that should be done.
“When I counsel a patient who’s now undergoing their first treatment for advanced bladder cancer, I’ll often encourage them to undergo genetic testing, mainly because we may find a genetic marker that is present in their cancer that might help me direct them toward a specific clinical trial that involves a drug that is specific for their genetic mutation,” explains Dr. Balar.
Dr. Balar also recommends genetic testing for any patient with stage II or greater cancer. “I advocate for early testing to have that information available early on so that if it’s needed, that information is readily available to make treatment decisions.”
If you’ve been diagnosed with bladder cancer, talk to your healthcare team about the benefits and limitations of genetic testing.