Genetic testing for cancer survivors: harnessing the latest in guidelines, technology
Click Here to Manage Email Alerts
Advances in genetic testing have created unprecedented opportunities for cancer survivors and their relatives to learn about individual or familial cancer risks.
During a presentation at Cancer Center Survivorship Research Forum, Kerry Kingham, MS, CGC, discussed ways in which current genetic tests offer greater insight at a more affordable cost.
“Genetic testing used to be thought of as one-and-done, and it turns out that’s not the case,” Kingham — lead cancer genetic counselor for the clinical cancer genetics program and clinical assistant professor of pediatrics at Stanford University School of Medicine — told Healio. “As technology gets better, our ability to detect things gets better at finding things. It not only helps the patient but also their family.”
Guideline changes
Some cancer survivors who stand to benefit from innovations in genomic profiling may not have received this testing at diagnosis due to ineligibility under guidelines at the time, Kingham said.
However, guidance continues to evolve.
“For example, the guidelines now say if you are 50 or younger with colon cancer, you should be offered genetic testing for hereditary causes, whereas in the past you needed three relatives [diagnosed with the disease],” Kingham said. “A patient diagnosed 10 years ago never would have met those criteria. And because the tests were so expensive, most patients weren’t paying out of pocket if their insurance didn’t cover it.”
Another key guideline update is an expansion of the number of genes these tests can effectively assess. A patient who may have been tested at diagnosis for a more limited set of genes now might be eligible for more extensive testing.
“A patient may have had what we now consider incomplete testing — maybe they were tested for one or two of their genes,” Kingham said. “Now, we’re testing for 25 or more genes. We’re casting a wider net.”
More in-depth examination in the form of RNA analysis also adds to the amount of information available through genetic testing, Kingham said.
Although most labs maintain there is still a small probability that adding RNA to a test will find a pathogenic variant, this technology nevertheless “gives a slight edge,” she said.
In some cases, patients with prior negative results through genetic testing may benefit from retesting using more updated technology, Kingham said.
“Sometimes patients will come to us and say, ‘I was already tested for Lynch syndrome’ or ‘I was already tested for BRCA,’” Kingham said. “Now we have improved ability to detect these things. Just because it was negative before doesn’t mean it will be now. The genes don’t change, but our tests get better.”
Revisiting test results
As patients with cancer move into survivorship, the interval between visits to their oncologist tends to increase. For this reason, it may be valuable for clinicians to check whether a patient’s genetic testing is up to date and optimized by the latest technology, Kingham said.
“Every time the patient comes in, just take a look at it,” she said. “Hopefully, some oncologists have a genetic counselor they can consult with. Most genetic counselors are OK [with] a physician calling us about whether they should send a patient over.”
Knowledge of a patient’s most recent genetic testing status also can help inform and optimize a patient’s cancer treatment regimen, Kingham said. If a cancer survivor is subsequently diagnosed with a new malignancy, having the most recent information about their genetic status can help expedite adoption of the most effective therapies.
“For instance, [poly(ADP)-ribose polymerase (PARP)] inhibitors for some of our BRCA carriers can be very useful,” she said. “It’s been amazing to see the shift from a downstream thought about genetic testing to, ‘Hey, this patient has a new diagnosis — we need them tested immediately,’ because it’s going to change what we would use.”
For more information:
Kerry Kingham, MS, CGC, can be reached at Stanford Healthcare Cancer Genetics Program, 900 Blake Wilbur Drive, Palo Alto, CA 94304; email: kkingham@stanfordhealthcare.org.
Collapse
Kingham K. Assessing genetic risk. Presented at: Cancer Center Survivorship Research Forum; Sept. 11-12, 2023, Stanford, California.
Click Here to Manage Email Alerts