The recent years have seen cancer genetic testing become an archetypal disease prevention tool. By testing your DNA for specific inherited mutations, the test gauges your risk for developing specific cancers, including breast, ovarian, colorectal, or prostate cancer. Understanding your genetic risk allows you to make better lifestyle choices for your life, seek early intervention, and even prevent getting cancer in the first place.
What Is Cancer Genetic Testing?
Cancer genetic testing is a medical test that looks for inherited changes in an individual’s DNA that may place them at increased risk of developing cancer. In contrast to routine cancer screens, which detect tumors or abnormal conditions that already exist, cancer genetic testing detects risk before signs and symptoms appear.
The test will draw blood or saliva, which in the lab will be analyzed for changes of specific genes that are linked to inherited cancer syndromes—i.e., BRCA1 and BRCA2 (breast and ovarian cancer), MLH1 and MSH2 (Lynch syndrome and colon cancer), to name a few.
Who Should Receive Cancer Genetic Testing?
Not everyone needs cancer genetic testing, but for an individual with the following risk factors, it can be very helpful:
- Early age cancer history (usually <50 years old)
- Number of relatives within one family having the same/similar cancer
- Written familial history of genetic cancer gene mutation
- Certain races, e.g., Ashkenazi Jewish background, with higher probabilities of BRCA mutations
- Higher than one family cancer history
If you belong to one of the above categories, you should discuss with a doctor or genetic counselor whether or not cancer genetic testing is appropriate for you.
Benefits of Cancer Genetic Testing
There are a number of benefits of cancer genetic testing, including:
1. Early Detection and Prevention
Being aware that you are at higher genetic risk for cancer provides you and your physician an opportunity to act preemptively. They may include more intense testing (colonoscopies or mammograms, for instance), all the way up to lifestyle modification, or even preventive surgery to remove the threat of cancer.
2. Individualized Medical Care
If you carry a gene mutation, your treatment plan might be modified accordingly. For example, individuals with BRCA mutations benefit from some of the targeted treatments, such as PARP inhibitors.
3. Informing Family Members
Your test result can alert family members to their risk. Since inherited mutations get transmitted to family members, they might also undergo cancer genetic testing to determine their risk and prevent it.
4. Peace of Mind
For some, the test will be reassuring with low genetic risk. Even if you are at higher risk, knowing allows you to plan, not live in uncertainty.
What to Expect During the Testing Process
The cancer genetic testing process generally includes the following steps:
1. Pre-Test Counseling
Before the test, you will have a genetic counselor go over your family and medical history with you as well as the potential results, risks, and benefits of the test so you will be ready for whatever the results may be.
2. Sample Collection
You will provide a blood or saliva sample that will be analyzed by a laboratory.
3. Results and Interpretation
Results usually take a few weeks. When they’re ready, a genetic counselor will meet with you and go over what they mean.
Results usually return as one of the following:
- Positive: A mutation that increases the risk of cancer is detected.
- Negative: No harmful mutations are detected in tested genes.
- Variant of Uncertain Significance (VUS): A genetic change is detected, but its impact on cancer risk is unknown.
Limitations and Considerations
Even though cancer genetic testing is robust, it’s not perfect. Keep the following few limitations in mind:
- A negative test isn’t always confirmation you have no risk. You’re still at risk of developing cancer from causes other than genes or mutations the test can’t find.
- A positive test isn’t always a sign you will develop cancer. It merely means your risk level is higher than average.
- Emotional impact. It is upsetting to hear of greater risk. Psychological guidance and assistance throughout the course are well worth it.
Cost and Insurance Coverage
The cost of cancer gene testing is often high, depending on how many genes are examined and which lab is used. Fortunately, most insurers now cover testing for patients with specific risk factors. It’s best to call your insurer ahead of time, and your doctor or genetic counselor can help with insurance pre-authorization.
Next Steps After a Positive Test Result
If your test indicates a genetic mutation that increases your cancer risk, your physician will have a sit-down with you to develop an individualized plan to reduce that risk. That may involve:
- Regular and early cancer screening
- Chemoprevention, or risk-reducing medication
- Adjustment of diet, exercise, and smoking
- Preventive surgery (such as mastectomy, oophorectomy)
Your family members also may be advised to undergo cancer genetic testing, especially first-degree members like parents, siblings, or children.
The Future of Cancer Genetic Testing
Technology is increasingly making cancer genetic testing common, accurate, and widespread. Multi-gene panel testing, in which multiple genes are screened at once, is becoming very common. We will have more personalized medicine based on an individual’s genetic predisposition in the coming years.
Research is also exploring genetic testing to enable the prediction of therapeutic response and guide decision-making for immunotherapy, the possibility of enhancing survival and minimizing unnecessary treatment.
Conclusion
Genetic cancer screening is an active way of knowing about your risk based on inherited factors and what you can do to control them. Not everybody, however, those with a dense family or individual history of cancer can benefit quite a lot by what it offers. Under a doctor’s supervision and keeping medical as well as emotional considerations in mind, you can employ genetic testing to create positive, affirmative choices regarding health.
If you suspect you could derive some advantage from cancer genetic testing, speak with your physician or a trained genetic counselor. Your DNA contains vital information—not only about what happened in the past but about the future.
