Expert Discusses Role of Genetic Testing in Detection and Prevention of Pancreatic and Other Cancers

Jennifer Geurts, MS, CGC

Jennifer Geurts, MS, CGC

Genetic testing can play an important role in the management of patients with certain cancers, as well as help inform preventative measures for family members who may be at risk of developing cancer, explained Jennifer Geurts, MS, CGC.

Identifying select mutations in patients with pancreatic, breast, ovarian, and other cancer types, can help physicians select the best treatment for each individual patient. In some cases, these results can impact the decision of whether surgery or a precision medicine approach is right for an individual patient. For example, patients with pancreatic cancer who have aBRCAmutation could be eligible for a PARP inhibitor while patients with Lynch syndrome may best be treated with an immunotherapy.

Additionally, genetic testing can help determine what types of screening methods would be best for family members that could be at risk for cancer. For those who have cancer in their families, genetic testing can help shed light on which individuals are at a greater risk of developing cancer. Providing the right type of screening can ultimately help in the prevention of developing cancer or detecting it early on, said Geurts, a genetic counselor at the Medical College of Wisconsin.

In an interview withTargeted Oncologyduring the 4^thAnnual School of Gastrointestinal Oncology meeting, Geurts discussed the current role of genetic testing, both in patients diagnosed with cancer, as well as family members that could be at risk of developing cancer. She also highlighted how genetic counseling can impact treatment decisions in patients with pancreatic, breast, and ovarian cancers.

TARGETED ONCOLOGY:What types of genetic testing are currently being used in cancer care?

Guerts:We talk about 2 different types of genetic testing. One is called germline genetic testing where we are evaluating to see if a patient has a hereditary predisposition to cancer, which is something they would have inherited from either their mother or father’s side of the family, typically. We contrasted that with what is called somatic testing, or molecular profiling, where we are actually doing genetic testing in the tumor. There are a couple different methodologies that are used, [such as] DNA next-generation sequencing (NGS) or they might also include RNA sequencing or proteomics to analyze the changes that have occurred in the tumor and what treatments may be the most effective in fighting that cancer.

TARGETED ONCOLOGY:Is this testing more commonly done in-house or sent out to a lab?

Guerts:With most of the testing, whether it is germline genetic testing or molecular profiling on a somatic tissue, it’s typically sent out. There are a small handful of laboratories in the nation that specialize in doing this sort of testing. It’s rather involved and can be costly, ranging anywhere from a couple hundred dollars to a couple thousand dollars, depending on the test that is pursued, so most of these tests are sent out to specialty laboratories.

TARGETED ONCOLOGY:How can the results of genetic testing be used?

Geurts:There are several reasons that we pursue germline genetic testing. One is [to see] if we can better care for the patient and if the genetic testing is going to impact their management. Sometimes, genetic testing may help to inform what kind of surgery a patient should have or what kind of medications they need to be taking if they are newly diagnosed with cancer.

For patients who don’t have cancer, genetic testing can also be valuable to help inform us what sort of screening we should be doing to detect cancer early or even for prevention options to possibly do something to prevent those cancers from happening all together. An example of that would be when we are doing a breast cancer gene testing for families that have a history of breast and ovarian cancer. Typically, what we are trying to do is identify those who may be at a higher risk for cancer in the family. In the example of ovarian cancer, if a woman is done having her children and is getting closer to menopause, we can remove the ovaries and tubes to prevent ovarian cancer from happening in those breast mutation gene carriers, because breast cancer is linked to ovarian cancer in most cases.

TARGETED ONCOLOGY:Are there any challenges associated with interpreting the results of genetic testing?

Geurts:Interpretation of genetic test results is challenging our understanding of genetics as genomics evolve. We learn more every year as more people are tested, and we have more of an appreciation of the complexities of the genetics both in the germline and somatic cancer cells. In interpreting testing, the one thing we have to appreciate is there are a lot of variations in DNA, and not all variation is bad. We have to rely on the laboratories where the genetic testing is being performed to make sure there is a quality in the interpretation of the variants. [From this,] we can understand which variants are going to be classified as pathogenic, or you might hear the term mutation that cause disease, then which variants are benign, or may also be called polymorphisms that don’t cause disease and are tolerated. That complexity is there, and we need more data analysis and more understanding of reference sequence in the general population, different ancestries, and ethnic populations to know what normal variation looks like, so we can help interpret when we do have a variant if that truly is leading to cancer or not.

TARGETED ONCOLOGY:How do you see the use of genetic testing evolving moving forward?

Geurts:I think genetic testing in the future will have much more methodologies. Currently, we do NGS and that technology has been clinically available for over 5 years now. That’s a great way to detect sequence variation in DNA, and more recently they are using bioinformatics to better understand structural rearrangements or deletions or duplications in the DNA, which is important as well. Going beyond the DNA is what the future holds. Looking at proteins, looking at epigenetics, methylations of our DNA, and certainly RNA, is the next big thing to come so that we can understand the next big thing as it happens, as our DNA is translated, and how that actually affects the proteins in the cell.

TARGETED ONCOLOGY:What was the take home message from your presentation at SOGO?

Geurts:My primary focus is in pancreas cancer, so what I’m really hopeful for is that providers understand, for individuals with pancreas adenocarcinoma, the new guidelines that are out from NCCN state that all those patients should be offered genetic testing, and that’s germline testing. There are a couple reasons for that; the first is if we can identify a germline gene mutation in that patient with pancreas cancer, we may be able to offer them a precision therapy. In the example of theBRCA-related gene mutations, we can offer PARP inhibitors, or in the example of the Lynch syndrome genes where the tumor is demonstrating microsatellite instability, maybe we can offer immunotherapy. There’s going to be more and more discoveries as we move forward for our patients with pancreatic cancer, and that’s a group of patients that really need those latest and greatest treatments available right now because it is such a hard disease to treat.

Also importantly, when it does run in families, pancreas cancer is devastating. People have seen their loved ones for generations be affected by this cancer, so we want to be able to offer family members early detection and prevention strategies so that what has happened for the past generations doesn’t have to happen in the future. That’s another area where germline genetic testing can be used to help inform risk and management to keep members healthy.

TARGETED ONCOLOGY:What are some of the questions you are asked the most in regard to genetic testing?

Geurts:Often patients will ask me why I wouldn’t pursue genetic testing. What are the reasons not to? Sometimes the cost can be a barrier, but as I mentioned before, the costs are coming down considerably, particularly for germline genetic testing. Most of our patients are covered by their insurance if they meet certain criteria or they may have a maximum out of pocket of just a hundred dollars.

The other reason that patients are hesitant to do genetic testing is that it could provide information regarding their family members and risk for developing cancer. Emotionally, this can be a lot to handle, particularly when that patient has cancer themselves; talking about the chance that it may be passed on to their children can be upsetting. We offer pretest genetic counseling to really walk through the implications of that.

Also, we talk to families about risk of genetic discrimination. The Genetic Nondiscrimination Act was passed in 2008 federally, which prohibits against health insurance companies and employers from using genetic information against an individual. That’s a really important piece to have in place so that people have their health insurance and can keep their health insurance moving forward without having to worry about risk of discrimination by their employer.

The other question I get often is who is appropriate for genetic counseling and testing. The criteria for who gets referred for genetics has been broadening in recent years. Certainly, any person that has been diagnosed with pancreas adenocarcinoma is a candidate for genetic counseling and testing. Likewise, in the case of ovarian cancer, epithelial type, we see all of those patients regardless of their familial history or age at diagnosis. Those are 2 examples of cancers that we would offer genetic testing for everybody.