Germline Testing: When to Trust a Patient’s Gut

Oncology nurse practitioners should be on the lookout for cancers that are recommended by the NCCN for germline testing, but should also be inquisitive about a patient’s personal and family history to determine whether germline testing may be appropriate, said an expert.

Suzanne Mahon, DNS, RN, AOCN, AGN-BC, FAAN, spoke with Oncology Nursing News regarding when to order germline testing for patients with cancer. She emphasized that simply asking a patient if they have a family history of cancer is not enough.

Instead, providers should open up a conversation with patients about their family history, asking questions about who in their family is alive and has certain conditions.

Mahon also pointed out that certain traits that should raise the question of whether germline testing is necessary are often overlooked, such as having at least 20 adenomatous polyps over a patient’s lifetime.

Mahon, who is a professor in hematology and oncology from Saint Louis University School of Medicine, presented research on genetics in cancer at the 50th Annual Oncology Nursing Society Congress.

Transcript

If you’re looking at a somatic report, things that you always need to do … [are] you need to look at the [patient’s family history.] Do they have one of those cancers that just automatically should be germline tested? So medullary thyroid cancer, pheochromocytomas, triple negative breast cancer, metastatic prostate cancer — there’s a laundry list on the NCCN guidelines if they have one of those cancers.

Whether you’ve done somatic biomarker testing or not, that’s an automatic referral. We really need to get in the habit of doing a full three-generation pedigree. If you just ask someone, “Oh, is there any cancer in your family?” we would all miss things.

But you so you have to systematically go through: how many siblings [does the patient have]? Are they alive? What is their health?

We need to really, then, look at that family history. Do they hit criteria for testing just based on personal or family history? Then we also need to think about the pathology of their tumors, as I said, triple-negative breast cancer, metastatic prostate cancer, the one that gets missed all the time — people that have 20 or more adenomatous polyps, colon polyps over a lifetime — they should be getting germline testing.

If your patient hits any of those criteria, you need to automatically refer them when you look at the somatic report. First of all, do they have an alteration in a gene associated with germline risk? Which means you need to know which genes are potentially associated with germline risk. And if they do, even if it’s not really concordant with the family history, that’s a reason to refer.

And finally, if they have a high variant allele frequency, especially in a gene associated with germline risk, that would be a reason to refer. And I always say, listen to the patient. If the patient is asking you, “Should I have germline testing?” or “Should I have testing to see if my kids are at risk?” Because that’s usually how the how the question gets asked, you have to listen to your patient and say, “You know what? We can explore that and not eliminate that.” Sometimes patients have some gut reason. They don’t quite explain it to you, but it’s there.

This transcript has been edited for clarity and conciseness.