A liquid biopsy is an innovative tool that provides insight into breast cancer without the need for surgery or traditional needle biopsies. As cancer cells die, they release tiny fragments of their DNA into the bloodstream, known as circulating tumor DNA (ctDNA). In many ways, ctDNA acts like a window into breast cancer, helping guide patients towards more personalized and effective care.
By analyzing ctDNA through a liquid biopsy, doctors can gain valuable insights into how the cancer is growing, what mutations it has and how it’s responding to treatment or whether it may be returning.
In this episode of Breast Cancer Breakthroughs, we learn more about ctDNA with former Komen Scholar Daniel F. Hayes, M.D., and medical oncologist Erin Cobain, M.D., who explain how ctDNA can be used to track tumor activity in the blood through a liquid biopsy and the potential it has for patients. We also speak with medical oncologist Seth Wander, M.D., Ph.D., about the SERENA-6 clinical trial, which is testing to see if ctDNA can be used to monitor for progression of metastatic breast cancer (MBC).
Providing Doctors with a More Complete Picture
When Komen Advocate in Science Meryl Weinreb received her first breast cancer diagnosis 37 years ago, she received the same treatment as everyone else diagnosed with breast cancer.
“They sort of threw the kitchen sink at me,” she says. Meryl was later diagnosed two more times with two different types of breast cancer, which were also treated differently than they would be today.
Needle and surgical biopsies have long been and remain to be the standard of care for diagnosing breast cancer. They provide valuable insight into how a person’s breast cancer should be treated. According to Meryl, who has witnessed the evolution of treatment personalization through her diagnoses and more than 12 dedicated years as a patient advocate, “the experience was interesting because it gave me a perspective how things have actually changed a great deal over the last 37 years.”
However, these samples provide only a snapshot in time. Today, patients are excited about the potential of ctDNA and how it may help take personalized treatment to the next level. With a more complete picture of what is happening in the body at the moment of testing, doctors can provide more timely, targeted care that’s tailored to each patient.
Personalized Treatment Based on ctDNA
Since ctDNA comes directly from tumor cells, it can reveal genetic changes in the cancer cells that help doctors understand what’s fueling tumor growth. Liquid biopsies can provide a more detailed look into the tumor’s unique biology and valuable clues about how the cancer is behaving.
“You’re getting a more complete picture of what you’re dealing with genomically from ctDNA,” Meryl says. “As a result, I think you can get a much more personalized and targeted treatment.”
One of the biggest potential benefits of liquid biopsies is that they could allow doctors to modify patient care in real time. Because these tests can be done regularly and are minimally invasive, doctors could potentially monitor how a tumor is responding to treatment and see if it’s changing or developing any treatment resistance. This could be especially helpful for those who are living with MBC.
For example, in the SERENA-6 trial, researchers are testing if ctDNA can help detect very early signs of cancer progression in patients with hormone receptor-positive, HER2-negative MBC before progression is seen on a scan. First results from the trial showed that switching to a new drug called camizestrant based on this early indication of cancer progression delayed cancer progression longer than the group that remained on the standard treatment.
These results illustrate how treatment plans could be fine-tuned along the way, and if ctDNA reveals any new mutations, doctors could pivot to treatment options that are more likely to be effective.
A Less Invasive Approach
While tissue biopsies are reliable, they are often difficult to repeat, especially for patients who are weak or undergoing treatment. And with less frequent screenings, doctors cannot accurately determine if the cancer is progressing or responding well to treatment. For many patients, a liquid biopsy is a more appealing option, and one that can be done more often.
“We can do two or three tissue biopsies in a row, and most patients begin to say, ‘That’s enough. I don’t want you sticking needles in me anymore,’ but most people don’t mind the blood test,” Dr. Hayes says.
With routine blood tests, doctors can stay on top of what cancer cells are doing, without putting patients through the discomfort of multiple tissue biopsies.
A New Era in Breast Cancer Care
Blood biopsies that analyze ctDNA are ushering in an exciting new era in breast cancer care. And while early data shows promise, more long-term studies are needed to establish liquid biopsies as a trusted diagnostic tool. Thanks to ongoing research, liquid biopsies could potentially make it easier to detect, track and treat breast cancer, and bring us closer to a future without it.
“Research is the most critical and pivotal thing that we need to ultimately have a world without breast cancer,” Meryl says. “It seems very far off right now, but we’re making progress, and research will get us there.”
Learn more about ctDNA.
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