Medicine's Next Big Thing? Catching Cancer With Magnets -- In Depth Doctor's Interview | Medical News and Health Information

Reported April 27, 2011
Medicine's Next Big Thing? Catching Cancer With Magnets -- In Depth Doctor's Interview
John McDonald, Ph.D., professor of biology at Georgia Tech, discusses a potential treatment for ovarian cancer.

When you started this research was there a particular problem or something you were trying to solve or fix or change in terms of ovarian cancer and its progression?

Dr. John McDonald: The Ovarian Cancer Institute is focused on both early diagnostics and better therapeutics. As you probably know ovarian cancer is a disease that is usually not diagnosed until very late in its progression. The prognosis is very poor by that time. So, one area of interest for us is early diagnostics, which we are working on. But, even if that is successful, there is still going to be a number of patients that do not get diagnosed early and we have to come up with better therapies. One of the problems with ovarian cancer is it’s highly metastatic especially at late stages. And that occurs primarily due to cells sloughing off the primary tumor into the abdominal cavity and spreading to other organs, the omentum and the liver are primary targets. So, with technology that was established here by a postdoc, Ken Scarberry, in my laboratory using magnetic nanoparticles that we direct towards ovarian cancer cells, we are able to target the nanoparticles directly to the cancer cells. They attach to the free-floating ovarian cancer cells and then we can pull them out or sweep them out of the body in a magnetic field. That was the goal, to see if we could reduce the number of metastasizing cells and thereby increase the life span of the patients with the disease.

Please explain what a nanoparticle is? And why does it attach to a magnet?

Dr. John McDonald: A nanoparticle is just a generic term for a very small, microscopic size, particle. In our case, the nanoparticle we are working with is a magnet already. It can be magnetic if placed in an appropriate magnetic field. So, the concept is if we can target those magnetic nanoparticles to ovarian cancer cells they will attach to the free-floating cancer cells and then in a magnetic field we can sweep all of the cancer cells out from the abdominal cavity of the patient thereby reducing the probability of spreading to the liver, or the omentum.

Have you seen some early signs that this could actually work?

Dr. John McDonald: Yes, in preliminary experiments done in animal models, in mice, we’ve been able to increase longevity of the animals with ovarian cancer by about 1/3. So, if that is extrapolated to humans that could tremendously increase the life span of the patient with the disease. What we are hoping is that, by these kinds of technologies and by expanding the life span, we would convert cancer, ovarian cancer in particular, from a deadly disease to a chronic disease. That is, you may not ever completely get rid of it, but if we can treat it and expand your life expectancy there’s a good chance you’ll die of something else and not from the cancer. Therefore, it becomes a manageable disease. And we are hoping that this technology maybe one of the things that would lead us towards that end.

How do you envision the process working as far as introducing the use of the magnet and getting the particles out?

Dr. John McDonald: The way we would envision this working is not to add the particles into the patient directly, but to do it in a device that would be outside the body. There would be a perfusion system, something analogous to blood dialysis so that you have perfusion of the fluid being pumped through the abdominal cavity and out. When the fluid comes out of the patient, it would go through a chamber where the magnetic nanoparticles would be added. They would attach to the cancer cells that are floating by and then there would be a second chamber, a magnetic field chamber, where all the cancer cells would be trapped. And so by this process we would be sweeping out or cleaning out the abdominal cavity of any free-floating cancer cells.

One more time about how the perfusion would work and how you would trap the cancer cells.

Dr. John McDonald: The plan would be to set up a system analogous to a dialysis system where patient fluid would be perfused through the patient, it would come out into a chamber where the magnetic nanoparticles would be added, they would complex with the cancer cells, bind to the cancer cells and then it would go into a magnetic field where they would be trapped so that we would be screening or sweeping the cancer cells out of the fluid. The goal would be to reduce the number of free-floating cancer cells in the abdominal cavity of the patient, thereby, reducing the chances of metastasis or spread.

How far away is this in terms of being a real possibility as an option for treatment?

Dr. John McDonald: We’re at the stage now where we are working with engineering firms to scale up the device that we were using on animals, up to the size that could be used on humans. That should take a couple of years to get a prototype device. At that point we should be able to move into stage one trials. If everything goes well, I think we’re looking at five years down the road when we may be able to introduce this into clinical practice.

Do you think that this could be a pretty big breakthrough for ovarian cancer?

Dr. John McDonald: We think so because most ovarian cancer patients do not die from the primary tumor. That can be removed or treated effectively with chemotherapy. The problem is the metastasis. If we can reduce the level of metastasis in these patients, we think we can significantly increase their life span. And, as I said, hopefully they’ll die of something else not of ovarian cancer.


Medicine's Next Big Thing? Catching Cancer With Magnets -- In Depth Doctor's Interview | Medical News and Health Information