Recently, an innovative non-invasive treatment has been proposed for cancer based on the continuous application of electric fields of very low intensity at frequencies of between 100 and 300 kHz using portable devices that patients wear during their daily activities.

These electric fields are known as Tumour Treatment Fields (TTFields) and their effect on tumour growth is thought to be due to the inhibition of cell division (mitosis).

In a study published in April in the journal Bioelectrochemistry, Quim Castellví and Antoni Ivorra , researchers of the Biomedical Electronics Research Group  (BERG), at the Department of Information and Communication Technologies (DTIC) at UPF, together with Mireia M. Ginestà and Gabriel Capellà, researchers of the Catalan Institute of Oncology at Hospital Duran i Reynals, have conducted an in vivo study in mice in which pancreatic tumours of human origin were implanted beneath the skin.

The application of electricity to organisms always generates heat and the aim of the research was to ascertain whether the beneficial effects of TTFields are caused by the temperature increase caused by the electric field or by the direct effect of electric fields on the tumour.

For the experimental study, the treatment devices were attached to the backs of the mice - which had previously been implanted with the tumour - using a silicone harness. Thus, for a week, a group of mice was treated with slight hyperthermia (41°C), while another group received TTFields treatment (6 V/cm, 150 kHz) to monitor the growth of the subcutaneous implant in the two groups. 

The results of the study showed that, alone, TTFields treatment did not produce any significant effect, but the combination of TTFields and chemotherapy did demonstrate a delay in tumour growth compared to the animals treated only with chemotherapy (47% average relative reduction of tumour growth).

The work, as Ivorra explains, has concluded that "the combination of chemotherapy and TTFields shows a beneficial effect, delaying pancreatic tumour growth in an in vivo animal model and, contrary to what we thought, this effect does not seem to be related to the induced increase in temperature".

Ivorra adds, "we, who are researching into the application of far more intense electric fields (hundreds of times higher) for the removal of local tumours using the electroporation phenomenon, were surprised by the impact of TTFields".

The positive effect of TTFields, though moderate, could offer new treatments for malignant tumours. In fact, it is already being tested clinically for the treatment of glioblastomas, one of the types of brain cancer with the most unfavourable prognosis.

Reference work:

Quim Castellví, Mireia M. Ginestà, Gabriel Capellà and Antoni Ivorra (2015), " Tumor growth delay by adjuvant alternating electric fields which appears non-thermally mediated",  Bioelectrochemistry, 105, pp. 16-24. Doi: http://dx.doi.org/10.1016/J.bioelechem.2015.04.006.