Genetic Testing Is Suggested First Step Upon Ovarian Cancer Diagnosis

Leigha Senter, MS, LGC

Genetic testing should be given to all patients diagnosed with ovarian cancer in order to identify optimal treatment strategies, as well as to inform patients’ family members about their potential cancer risks, explained Leigha Senter, MS, LGC.

“It's unanimous that all women with ovarian cancer should at least be offered BRCA1/2 testing,” said Senter. “That has implications for the patient, her future cancer risk, potential treatments for her cancer, and her family members.”

Senter recommends that all patients receive tumor testing as well as germline testing—if the resources are available—to get the most well-rounded overview of an individual patient’s disease.

“Some [physicians] might start with tumor testing and [then switch] to germline testing, or vice versa. The point is to do the best that you can with the resources that you have available so that all of your patients have access to the care that they need,” Senter added.

In an interview during the 2019 OncLive^® State of the Science Summit™ on Ovarian Cancer, Senter, a genetic counselor, associate professor of clinical, human genetics at The Ohio State University Wexner Medical Center, discussed the current state of genetic testing for patients with ovarian cancer.

OncLive^®: What genes beyond BRCA are being explored in the ovarian cancer space?

Senter: There are a handful of other genes that work in a very similar way to BRCA1/2, and most of them contribute a lesser risk to cancer overall, but they still usually contribute a much higher risk [of cancer] than the general population. A mutation in one of those genes cannot only potentially explain where the cancer came from, but it can also give some guidance regarding whether to screen for other kinds of cancer. A mutation can also determine whether family members need to be tested, screened, or think about preventive surgeries. We're learning more about these genes, and it's likely they may become targets for therapies down the road.

What questions with BRCA1/2 mutations still remain?

We're essentially looking for biomarkers that might predict response. Not all BRCA mutations behave the same way in a cell. Likewise, the genes that work in the same pathway may not behave the same way. Those molecular studies are really important. When we're looking at clinical trials and seeing how they define the biomarkers, it can be different with every single study. There are so many options out there. The end goal is to determine what the molecular signature is to choose the right therapies. There's still a lot of progress that we need to make.

How widespread is genetic testing for ovarian cancer?

We have more incentive to do a good job. Up until recently, we have known for a long time that we should be offering [genetic testing] to all patients, but we weren't doing that, unfortunately. A lot of centers have gathered their troops together to make it more accessible to their patients, but we still have some progress to be made.

Recent data suggest that less than 50% of women with ovarian cancer are getting germline testing; that has improved significantly over the years. Some centers have improved their rates to 80% or 90% by making minimal practice changes, and making sure that somebody is the champion at their center to be in charge of it.

Is there an optimal testing method that should be followed regarding germline and tumor testing?

In an ideal situation, everybody would have both germline and tumor testing. It's not always feasible or practical and there are a lot of very unscientific things that make [doing both tests] a burden—such as payer policies, logistics in the clinic, and other things that you have to do. By doing just germline testing, you're going to miss a large percentage of patients who might have a somatic mutation and be a good candidate for a given therapy.

However, if you do tumor testing alone, you can't distinguish if any mutations identified in a tumor are germline or not; therefore, you're missing opportunities to prevent cancer in family members. There are certain kinds of mutations that are not easily detectable in tumor tissue using the current technology. Conducting both [germline and tumor testing] is best, but any is better than none.

How is microsatellite instability (MSI) testing being conducted in ovarian cancer?

MSI testing is part of some of the tumor tests available and it has huge treatment implications. Fewer ovarian cancers than endometrial cancers are going to fall into that category. However, if you're doing the test anyway, make sure that [MSI] is a part of it for that small percentage of patients for whom it might have a big impact.

What advice can you provide about conversing with patients about getting genetic testing?

Understanding the benefits and limitations of the testing is key. Most patients with ovarian cancer are eager for answers. It's not that they don't want to have genetic testing, but it’s tricky when we get to the point of having the results in front of us, explaining it to them, and making sure that they can spread the word amongst their family members.

[It is also important to] understand the limitations of the test. Even with a negative or positive result, [we need to understand] the importance of testing. Make [the positive result] not a “doom and gloom,” scary thing; rather, [use it to inform patients] that having the information can allow them to make decisions to keep themselves [and their family members] healthy. Helping patients step by step through those discussions is really helpful.