The researchers tested their method on patients undergoing radiotherapy, including several HPV-positive patients. HPV stands for human papillomavirus, which can also cause cancer. The number of HPV DNA fragments found in the blood allowed the researchers to observe the development of tumors. 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 following applies to practically all cancers: the earlier they are detected, the better the chances of effective treatment.
It is equally important to individually assess the benefits and risks of individual forms of therapy for the person affected during cancer treatment and to regularly monitor the success of the treatment.
Numerous methods are available in cancer medicine today for this purpose, in particular imaging procedures or invasive measures such as tissue biopsies, punctures and endoscopies.
Analyzing gene fragments in the bloodstream
Researchers at the University of Zurich (UZH) and the University Hospital Zurich (USZ) have now developed a new method: a type of “liquid biopsy” that is used to examine blood samples rather than organs or tissue.
Specifically, free DNA fragments circulating in the blood – i.e. snippets of genetic material from a patient’s cells – are sequenced and analyzed.
“In future, our method can be used for risk assessment, treatment monitoring in aftercare and early detection of a relapse. And basically for all tumors,” says Zsolt Balázs, co-first author of the study, from the Institute of Quantitative Biomedicine at UZH.
As the method is based on blood samples, it is less invasive than tissue biopsies, for example.
In addition, blood samples can be taken more quickly and easily in everyday clinical practice, as fewer appointments need to be organized for diagnostic interventions, which saves patients long waiting times.
Tailor-made treatment approach
The new analysis method for liquid biopsies can help to better define tumor spread and activity in order to develop individually tailored treatment strategies for patients in the future.
“This will allow us to see earlier and faster how much the cancer is spreading in the body and how well the patient is responding to the chosen treatment, or whether there will be a relapse,” summarizes Balázs.
In the laboratory, the researchers examine the genetic material snippets circulating freely in the blood sample for changes in the DNA that are typical for the respective, specific type of cancer: In the method used, on the one hand for changes in the quantity and length distribution of the circulating DNA.
“With liquid biopsy, we can distinguish aggressive tumors with metastases from less severe cancers – possibly even earlier than is possible with imaging techniques,” says co-first author Panagiotis Balermpas, Professor in the Department of Radiation Oncology at the USZ.
Increased focus on patients’ quality of life
The researchers tested their method on patients who were treated with radiotherapy.
They also found several HPV-positive patients in this group.
HPV stands for human papillomavirus, which can also cause cancer.
The amount of HPV genetic material they were able to find in the blood samples allowed the scientists to track the progression of the tumor burden.
In the case of tumors in the head and neck area, an increased concentration of HPV DNA could be an early signal for a relapse of the tumor, which could be combated with the help of immunotherapy. “The more a tumor metastasizes, the worse the patient’s quality of life. This also applies to local recurrences that are not detected early. The key is to individualize treatment as much as possible, keeping in mind the potential benefits of all therapies and their impact on the patient’s quality of life,” concludes Balermpas, who was primarily responsible for the treatment of patients with head and neck tumours within the study. Publication
