Can the blood of patients with severe forms of cancer be filtered using special techniques to “intercept” and halt circulating tumour cells (CTCs), thus preventing them from forming metastases in other organs?
The idea has been under consideration for some time, but haematologists at the University of Oklahoma Health Sciences Center (United States) have only recently actually put it into practice, achieving positive results in a 51-year-old female patient with aggressive pancreatic cancer. And they only decided to publish the results of their research – in the scientific journal Oncotarget – in late July 2025, after a year of treatments and observation.
Imaging showed that the disease remained stable over the 12-month period, with no new metastases detected. The woman also reported improvements in appetite, energy levels and pain control. Her opioid painkiller use was reduced by 90%.
Blood tests also confirmed a reduction in circulating tumour cell (CTC) levels after the treatment.
This observation supports the idea that removing circulating tumour cells might help limit cancer progression in some patients, the doctors write. However, given that this is a single clinical case report, larger studies will be needed to evaluate the effectiveness of this approach. Nevertheless, the results achieved bring hope, warranting further investigation of the technique by applying it to other patients.
Pancreatic cancer – and especially the most common form, pancreatic ductal adenocarcinoma – is one of the most insidious and difficult cancers to treat, as it is often diagnosed at an advanced stage, when metastases are already widespread and treatment options are very limited.
While conventional chemotherapy may slow progression in these patients, it causes severe side effects and doesn’t always produce lasting results.
The major challenge here, as we mentioned earlier, has to do with circulating tumour cells: fragments of tumour that break away from the primary mass and travel via the blood or lymphatic system. It is these cells that promote the formation of metastases in distant organs, turning a localised cancer into a disease that is much more difficult to control.
The patient treated at the university hospital in Oklahoma had poorly differentiated adenocarcinoma (one of the most difficult to treat) stage IV (the most advanced), with widespread metastases already present in the liver and lymph nodes. She was also suffering from severe abdominal and back pain. Having refused chemotherapy, she was proposed blood filtration by the doctors, using a device called Seraph® 100, with specially designed filters, connected to a haemodialysis machine. In this technique, blood is passed through special filters that trap tumour cells and harmful molecules – in fact, this equipment had originally been designed to remove bacteria and microorganisms from the blood in sepsis patients.
The woman received around ten treatments over the course of a year, both in the United States (under a trial protocol) and in other countries, where the filter is also approved for use in cancer.
Why filtering the blood also had positive effects on appetite and energy levels isn’t known: the researchers suggest this is probably because the filter membranes not only capture CTCs but also some pro-inflammatory molecules, which are always present and are responsible for symptoms such as severe fatigue.