This is one of those claims that seems a bit far-fetched at first glance. Dr. Elion Kirson and his colleagues used a device developed by Professor Yoram Palti of the Technion – Israel Institute of Technology to deliver electrical fields through direct contact electrodes to treat the worst forms of brain cancer – glioblastoma multiforme (GBM), and found that survival time doubled over historical controls.

I had a skeptical eyebrow half-cocked over this story – this is an impressive success over a very difficult to treat form of cancer, and the approach just seems a bit simplistic. But after reading the various papers I think there is some potential here. Like all preliminary data, this must be viewed with cautious optimism The GBM study was open-label, that means no control group, and was in a small number of patients (10). But any improvement in the survival time with GBM is impressive.

The putative mechanism of the alternating electrical fields is that they disrupt mitosis. When cells divide the chromosomes must go through a complex dance – they must line up precisely then duplicate and divide precisely, so that each cell gets one full copy of the genome. The hypothesis is that the alternating electrical fields, within a certain frequency range only, disrupt an important mechanism of signaling that is crucial to mitosis. This of course implies that electrical signaling is involved in the chromosomal dance of mitosis. An earlier study of the technology shows that the effect on mitosis is no thermal – the electrical energy is not just heating up the cells.
Disrupting mitosis is a classic approach to the treatment of cancer. Cancer cells rapidly reproduce – in fact pathologists will look for “mitotic figures” (cells undergoing mitosis) when looking at a biopsy slide to determine if the tissue is cancerous. Normal cells divide also, and this accounts for much of the side effects and toxicity of chemotherapeutic agents (for example, hair follicles also have rapidly dividing cells which is why chemotherapy can cause hair loss).

Brain cells, however, do not undergo much reproduction. This makes brain cancer, like GBM, and ideal candidate for this electrical treatment. Also, there is a technical advantage in that you can attach electrodes around the skull to surround the brain.

The electrical fields appeared to have two effects on dividing cells in vitro. The first is to stop the process of mitosis – which therefore would stop a cancer from growing. The second effect, however, is to kill cells that are undergoing mitosis. So the disruption of mitosis not only stops the process but causes the cell to break apart and die.

The study found that the 10 GBM patients had a median length of time to disease progression of 26.1 weeks; progression free survival at six months of 50 percent; and median overall survival of 62.2 weeks. This is slightly more than twice the historical data of 9.5 weeks, 15.3%, and 29.3 weeks, respectively. In the world of GBM treatment, a doubling of survival time is huge. But still, median survival was just 15 months. This is in the ballpark of other established and experimental treatments for GBM ( for example).

One advantage to the treatment is that it has few side effects (especially when compared to other cancer treatment modalities). The only reported side effect was a contact dermatitis from the electrodes, which responded to treatment with a topical cream.

The treatment is far from a home run, but enough of a clinical response (if it holds up with larger and controlled trials) that it is demonstrating a real effect. It is also a novel treatment approach. The hope is that because the mechanism of treatment is so different, it will have an additive effect to other treatments for GBM. Just like it is common to add chemotherapy to surgery and radiation therapy, perhaps soon tumor treating fields (TTF as it is being called) will become a standard fourth arm of cancer treatment.