The future of cancer treatment is here.
A new technology in cancer detection and monitoring called the liquid biopsy (or circulating tumor cell (CTC) count) can detect tumor DNA circulating in the blood before symptoms even arise, all by sequencing a person’s DNA through a simple blood test.
How is this possible? The idea for the test comes from a study conducted in the late 1990s. The study determined that fetuses shed little pieces of DNA into their mothers’ bloodstreams. It turns out that dying cancer cells do the same thing – they shed DNA into the bloodstream in amounts that are usually so small that they’re obscured by the healthy DNA in the blood.
The liquid biopsy finds and reads these tiny pieces of DNA by testing a small vial of patient blood with technology that quickly sequences DNA. With this technology, researchers can spot tumor DNA even when it’s present in trace amounts, detecting cancer earlier to improve treatment options and allowing for more information about the success of a chosen therapy.
The current state of cancer care and detection involves using standard diagnostics and choosing from several cancer therapies. However, these traditional diagnostics can take up to three months to reveal whether or not a treatment is working – a long enough time for cancer to grow and spread, making if difficult to determine when to change therapies. Not only could this new biopsy technique detect the presence of tumor DNA in the blood earlier, but it will also allow oncologists to determine earlier if the chosen treatment is working.
Additionally, a typical tissue biopsy involves analyzing pieces of a patient’s tumor, a process that can be incredibly invasive and even painful for patients. There’s also room for human error in the process – when physicians take samples, they can miss the spot where the cancer resides. The liquid biopsy test offers a less invasive option than tissue biopsy or CT scans.
Dr. Mehmet Toner, a liquid biopsy researcher, is part of an ongoing collaboration between the Massachusetts General Hospital’s Cancer Center and Johnson & Johnson. The collaboration is all about transforming a microfluidic chip system into an easy-to-use biopsy test.
While there are many different tests used to perform the same liquid biopsy analyses, the chip system is one of the most common. It uses minuscule channels carved into a silicon chip, coated with a special glue-like substance, to detect tumor DNA. When blood travels through the channels, the technology in the chip can pick up about 10 cancer cells per milliliter of blood in patients with metastatic cancer. Toner’s project hopes to make this technology even simpler for hospitals and clinics.
“This test gives us the ability to monitor treatment and make decisions about whether or not the treatment is working, which is critical for the future benefit of cancer patients,” says Toner. “We are looking at a technology that might make cancer a manageable disease.”
Toner notes that more evaluations are still needed for the test when it comes to determining accuracy and reliability. However, there are institutions offering the test already, including the Jefferson University Hospitals in Philadelphia and another private hospital in Hong Kong. Today, the test is FDA-approved for breast, colon and prostate cancers that have metastasized.
“This technology is here to stay,” Toner says. “It will only get better as we advance it over time.”
Soniya Shah is an on-staff contributing writer at MedTech Boston. She's a senior at Carnegie Mellon University pursuing a BS in technical writing. She has experience as a ghost writer and medical writer, and in developing software documentation.
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