Cancer is a disease that involves cells dividing faster than they should (check this out for a review of how cells divide) along with many other complicated processes. But if you simplify cancer to this one concept – cells dividing too fast – then you can think of interesting ways to kill cancer cells by targeting cells that are dividing quickly. In fact, many (if not most) current cancer treatments do just that – they create too much DNA damage for the cancer cells to handle, so the cancer cells kill themselves. There is a bit of a problem with this though – cancer cells aren’t the only cells that are quickly dividing. Hair follicles, cells in the lining of the gut and blood cells all also divide quickly. This is why non-specific cancer treatments like chemo that go throughout the body also end up killing these fast dividing cells, which is why cancer patients often lose their hair, have low blood counts and have gastrointestinal issues.Wouldn’t it be great if the cell division part of cancer cells could be more targeted, less toxic, and avoid many of the difficult side effects from cancer treatment? Scientists are working on a number of different treatments that do just that, but in this post I’m going to talk about one that is particularly interesting because it’s being used in clinical trials in our backyard at the Barrow Neurological Institute to treat glioblastoma multiforme (abbreviated GBM). GBM is the most common form and aggressive adult brain cancer. GBM has a terrible prognosis – with 50% of patients diagnosed dying within one year and 90% dying within 3 years. Standard treatment involves surgery to remove the tumor, and then radiation and chemotherapy treatment. Treatment is difficult, and because this is a brain tumor, there are additional challenges involving brain damage from surgery, radiation and/or chemo and getting drugs through the blood-brain barrier into the brain tumor.
A new treatment called NovoTFF (TFF stands for Tumor Treating Fields) goes directly after the dividing GBM cells. Receiving FDA approval in 2011, it is a device that is worn as a cap (see image at left) and uses a battery pack that can be worn in a backpack to create wave-like electronic fields that penetrate the brain. These fields disrupt the spindles that are responsible for separating the chromosomes during the cell cycle (see image above). There is also some evidence that these electric fields disrupt the cell membrane of dividing cells as well. Since the GBM cancer cells are dividing, they will be most likely to have their cell cycle disrupted and the cells’ natural response to this kind of major disruption is to die. This treatment has amazing advantages. Because it’s worn outside the body, NovoTFF isn’t invasive like surgery. It’s also just worn on the head so it won’t have side effects like the ones from treatments that go throughout the body. Also, the electric fields won’t affect cells that aren’t dividing (like most brain cells), so this treatment is less likely to cause damage to the non-cancerous brain cells. But does it work? Yes! In multiple clinical trials, this treatment was shown to slow the growth of recurrent GBMs and increase the length of progression-free survival compared to patients who did not use NovoTFF. The only disadvantage might be that the cap needs to be worn for 18 hours a day. Then again, if that 18 hours a day can prolong a patient’s life, the inconvenience might be worth it.
NovoTFF has been so successful that it’s also be tested in clinical trials for pancreatic cancer, ovarian cancer, mesothelioma, and brain metastasis from lung cancer. Obviously in these cases the device has been changed so that it attaches to the torso instead of sitting on the patient’s head. Research is also being performed by individual doctor’s to see if NovoTFF may work for newly diagnosed GBM patients or for other kinds of cancer.
If you want to learn more about Tumor Treating fields and this fascinating new treatment, check out this Ted Talk