An ultra-sensitive liquid biopsy test that assesses DNA shed by tumors in the bloodstream may help doctors better monitor how patients with advanced gastrointestinal cancers respond to treatment, UF Health Cancer Institute researchers have found.
“Our early findings are promising and may help advance more precise and individualized treatment monitoring strategies,” said Abdul-Qahar Yasinzai, M.D., a clinical research fellow at the UF Health Cancer Institute who presented the study Saturday at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.
One of the major challenges in cancer care is that after a patient starts a new treatment, they often need to wait several weeks to a few months before imaging can reliably determine whether the therapy is working.
The new project explores whether highly sensitive molecular assays may provide earlier insight into tumor response or progression by detecting changes in circulating tumor DNA in the bloodstream. The researchers are using a methylated circulating tumor DNA (mctDNA) assay developed by BillionToOne.
Unlike many traditional liquid biopsy platforms, the new assay does not require a prior tumor tissue sample, so it can be applied to many types of cancer. The researchers are exploring its potential use across multiple types of gastrointestinal cancers and studying how it may complement conventional imaging approaches like CT and MRI scans.
The team, which includes UF Health Cancer Institute researchers Thomas George, M.D., FACP, FASCO, Gahyun Gim, M.D., Meghan Ferrall-Fairbanks, Ph.D., Bruno Hochhegger, M.D., and Ji-Hyun Lee, Dr.PH, presented an analysis of 38 patients.
“In our exploratory cohort, we observed that rising tumor methylation scores were generally associated with disease progression and poorer outcomes, while declining scores tended to correlate with treatment response,” Yasinzai said.
The study introduces the tumor shed rate, which aims to better contextualize circulating tumor DNA with radiology imaging. The tumor shed rate combines mctDNA measurements with measurements of the tumor volume derived with artificial intelligence software. That allows researchers to better understand how different tumors biologically “shed” DNA into the bloodstream, as well as how liquid biopsy and radiology complement each other.
“This is important because tumors that are similar sizes may release very different amounts of circulating tumor DNA depending on factors such as tumor biology, treatment response and cancer subtype,” Yasinzai said. “By combining molecular and imaging data, the tumor shed rate may provide a more clinically meaningful framework for interpreting liquid biopsy results rather than viewing molecular measurements in isolation.”
The researchers will continue to analyze how the tumor shed rate can be used to assess cancer treatment responses.
The work received funding from the National Institutes of Health and the UF Health Cancer Institute.
