Researchers at the University of Zurich (UZH) and the University Hospital Zurich (USZ) have developed a new diagnostic method for cancer patients, a type of liquid biopsy that analyses blood samples rather than organs or tissues.
The new blood test could replace invasive measures such as tissue biopsies, punctures and endoscopic procedures when assessing the benefits and risks of individual forms of therapy and to monitor treatment success
The method sequences and analyses DNA fragments circulating in the blood of patients. “Our method can be used in the future for risk assessments, treatment monitoring during follow-up care and early detection of cancer recurrence, in principle for all types of tumours,” says Zsolt Balázs, co-first author of the study at the UZH Department of Quantitative Biomedicine.
In the laboratory, the researchers analysed the gene fragments circulating in the blood for changes in the DNA that are characteristic of the specific type of cancer. The method analysed alterations in the number and length distribution of the fragments. “The liquid biopsy technique enables us to discriminate between biologically less and more aggressive metastatic cancer disease – perhaps even earlier than using imaging technology,” said co-first author Panagiotis Balermpas, a professor at the Department of Radiation Oncology at USZ.
The researchers tested their method on patients undergoing radiotherapy, including several HPV-positive patients. The number of HPV DNA fragments found in the blood allowed the researchers to observe the development of tumours. For head and neck cancer, they found that a higher concentration of HPV DNA might be an early indication of cancer recurrence, which could be combated using immunotherapy.
“The more a tumour metastasizes, the poorer the patient’s quality of life. This also applies to local recurrences that aren’t detected early. It is key that we individualise treatment as far as possible, taking into account the potential benefits of all therapies as well as their influence on the patient’s quality of life,” added Balermpas, who oversaw the treatment of patients with head and neck tumours in the study.
- Balázs Z, Balermpas P, Ivanković I, et al. Longitudinal cell-free DNA characterization by low-coverage whole-genome sequencing in patients undergoing high-dose radiotherapy. Radiother Oncol. 2024 Jun 2:197:110364. doi:10.1016/j.radonc.2024.110364