Expanding Germline Genetic Testing in Oncology (Podcast)

Germline genetic testing is playing an increasing role in personalizing cancer treatment as well as identifying family member risks by identifying inherited gene mutations. As recommendations for germline genetic testing continue to expand, many eligible patients remain untested.

In a recent episode of Cleveland Clinic’s Cancer Advances podcast, Demitrios Dedousis, MD, from the Genitourinary Medical Oncology team discussed:

• Current testing indications
• Common gaps in implementation
• Clinical implications of identifying hereditary cancer predisposition syndromes
• How germline findings can influence treatment decisions, screening protocols and risk assessment for families

Click the podcast player above to listen to the episode now, or read on for a short edited excerpt. Check out more Cancer Advances episodes at clevelandclinic.org/podcasts/cancer-advances or wherever you get your podcasts.

Excerpt from the podcast:

Dale Shepard, MD, PhD:

We have these early ways to look for cancer, these early cancer detection tests, and the field of doing genomics and testing is exploding. What do you see the world looking like in five years or so?

Demitrios Dedousis, MD:

One area that I'm especially interested in is multi-cancer early detection testing. We're in the early stages of planning a study to try and use some of these multi-cancer early detection panels. They're usually serum based. It's usually a blood draw in people with hereditary cancer predisposition syndromes under the theory that these people have a much higher pretest probability, they have a higher risk of having cancer to begin with.

Surely this would be one of the populations that would benefit most from this testing if any population was going to. What we've come to is our first step would probably be to run some of these tests in people with a cancer predisposing gene change that already have cancer, because if our tests are not positive in those populations, they're not going to end up being very useful in any population. That's a project that we're in the planning stages on.

I hope that can become an adjunct to radiologic surveillance in cancer predisposition syndromes because it's difficult to have somebody get so many scans. It would be really nice if we could intersperse the scans with some blood tests. So, it remains to be seen how effective it'll be.

Unfortunately, they're not as great right now at detecting some of the common cancers like breast cancer, prostate cancer, localized cancers. They're not as good at picking up, which is a challenge, but it's also an opportunity. I also see the other change I see in the field, and I think it's coming, I think it's inevitable, I suspect everybody with a cancer diagnosis of any kind is going to get both germline and somatic genetic testing at diagnosis. At institutions, there was one out of Memorial Sloan Kettering where they do this. They do germline testing, a panel of about 80 genes, a fairly standard panel these days.

In anybody with any cancer, you find a hit rate of about 25%. Some of these might be incidental, but a few studies have found something like that. That's not bad considering some of the more obscure tests that are part of our standard internal medicine workups, and it can be helpful to the family and often it can be helpful to the patient.