Biomarker testing for endometrial cancer can provide important clues about how a patient may respond to different treatment options. Dr. Joshua Cohen defines biomarkers, explains how their detection guides treatment decisions, and clarifies the difference between a cancer’s grade and its stage.
Dr. Joshua G. Cohen is a board-certified gynecologic oncologist and Medical Director of the Gynecologic Cancer Program at the City of Hope Orange County. Learn more about Dr. Cohen
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Transcript
Katherine:
Dr. Cohen, what are biomarkers and what is their role in guiding endometrial cancer care and treatment?
Dr. Josh Cohen:
Yeah. Biomarkers are – and the term is a little broad. We’re actually getting a little bit more specific now, but biomarkers are a way – I would call it a description of what the tumor has in it. And we use biomarkers to determine whether patients will benefit from certain treatments. An example is something called mismatched repair deficiency. Mismatched repair deficiency is a way of describing the presence or lack of presence of certain proteins in the tumor. If certain proteins are lost in expression, meaning they’re not made in the correct manner, that’s a sign that you may benefit significantly from the immunotherapy.
So, that’s a biomarker for immunotherapy. There’s another marker called HER2. And this is a marker that’s also used in breast cancer. If someone has a tumor where HER2 is highly expressed in the tumor, that’s a biomarker that we can then use certain drugs that target HER2. And that’s a win because those drugs can be very effective.
In the same respect, if someone tests negative for HER2, we would not wanna use those drugs because they have risk and we know that those patients may not benefit as much. And so, that’s a shared decision-making approach based on a biomarker that we’re testing for.
Katherine:
Right. How and when is biomarker testing done?
Dr. Josh Cohen:
For endometrial cancer or uterine cancer – which I use these terms, essentially, interchangeable for the purposes of this talk – it’s essential and really this is where getting a second opinion can be important. But if you have an endometrial cancer diagnosis, you really should be talking to your healthcare provider about these markers: MMR deficiency, HER2 status, microsatellite instability – and these are the basic ones – TP53 or P53 status.
These are basic biomarkers we would want for almost all of the caners we’re testing for in uterine cancer. There’s something called POLE in uterine cancer. POLE is a molecular signature where if you test positive for POLE in the tumor, that may be a sign that you don’t need to use these other treatments, like radiation or chemotherapy. Maybe not. It’s worth a discussion, but it indicates possibly a more favorable prognosis with the tumor, meaning the tumor’s less likely to recur or spread throughout the body.
Katherine:
Are there biomarker tests used for early-stage cancer as – just a moment. Are the same biomarker tests used for early-stage cancer as for advanced or recurrent cancer, or does testing change over time?
Dr. Josh Cohen:
Testing changes over time, and there are two points I want to make about this question. There’s a difference between stage and grade. Stage is anatomically where cancer is located, and grade is what it looks like under the microscope.
Is it a high-grade cancer? Is it a low-grade cancer? You could have an early-stage cancer, meaning it’s a cancer confined to the uterus itself, but under the microscope it looks aggressive. The cells look like they’re dividing quickly.
Katherine:
Wow.
Dr. Josh Cohen:
Similarly, you can have an advanced stage cancer that spreads to the lymph nodes or something called the omentum, which is an apron that hangs off the colon, but the tumor under the microscope looks low grade. Depending on the stage and the grade, there are different biomarkers that we would test for.
So, you as the patient or a loved one of a patient should gather information about stage and grade and then talk to your healthcare team about what biomarkers make sense because you may have an early-stage cancer, but it may be a high-grade cancer that will benefit from biomarker testing to determine if you need some of these additional treatments to reduce the risk of the cancer coming back.