Women who have the most common form of secondary breast cancer and are doing well on treatment may be able to have their cancer monitored with a simple blood test rather than a CT scan, according to to a trial that’s taking place at The Christie NHS Foundation Trust.
The trial is co-led by The Christie and Sahlgrenska University Hospital in Sweden, in collaboration with University of Gothenburg and Linköping University. Researchers are looking at whether blood tests are as effective as a routine CT scan in terms of assessing disease progression.
Although very effective, scans are often uncomfortable and can raise anxiety levels while people wait for the results. Some scans also carry a small dose of radiation that could increase the chance of the patient getting cancer again in the future.
The trial has recruited 97 patients who will still have scans every 3 months as usual but will also have a blood test on the same day as the scan. The women on the trial have oestrogen-positive (ER+)/HER2-negative breast cancer. 80 per cent of women have ER+ disease and 15 per cent have HER2-negative disease.
The sample is then sent away for researchers to analyse for DNA fragments released by tumour cells into the blood circulation, referred to as circulating tumour DNA, as well as other biomarkers. These other biomarkers can provide information about a person’s cancer in order to determine whether the patient’s cancer responds to treatment or may be advancing.
According to The Christie, the three main biomarkers are:
- Circulating tumour DNA – as a tumour grows, cells die and are replaced by new ones. The dead cells get broken down and their contents, including fragments of DNA, are released into the bloodstream.
- TK-1 – an enzyme which is essential for DNA synthesis and cell repair. High levels of it in the blood can indicate that cells are growing whereas low levels are seen when cancers are controlled, particularly by the type of treatment used in this trial.
- CA 15-3 – a protein that can be shed from the surface of breast cancer cells into the blood. This test has been available for many years, but in this study it will be used combined with other biomarkers in order to better reflect the patients cancer.
Additional samples will be stored so that other, not yet defined biomarkers can also be tested in future.
The aim is to develop a biomarker-based prediction model that will inform the doctor whether the patient needs a scan. Scans can thereby be safely omitted as long as biomarker levels remain low and resumed when levels begin to rise indicating that the cancer is growing.
Dr Sacha Howell, Consultant Medical Oncologist at The Christie and co-Chief Investigator of the trial, commented: “Thanks to huge advances in breast cancer treatment, many women are living for many years with the advanced form of the disease.
“By evaluating whether a blood test can be used instead of routine scans to check for disease progression, we’re not only making things more convenient for patients, but are further limiting the risks and discomfort that come with routine scanning.
“Discovering and delivering robust, accurate biomarker tests is central to future cancer treatments. The more biomarkers we develop and deliver, the more targeted and personalised we can be in terms of diagnosing, treating, and monitoring cancer.”
Any patients interested in taking part in clinical trials should discuss this option with their consultant or GP. Not all patients will fit the criteria for a specific trial. While clinical trials can be successful for some patients, outcomes can vary from case to case.
More information about the trial is available at clinicaltrials.gov.
