By Steve Blanchard
Brain cancer can refer to cancer that starts in the brain, or cancer that starts elsewhere in the body and eventually spreads to the brain through the bloodstream. If a tumor originates in the brain tissue, it is known as a primary brain tumor; if it originates elsewhere in the body and spreads to the brain, it is known as a metastatic brain tumor.
Brain metastasis is more common than many think; one out of every four cancer patients will eventually experience it.
So how do doctors battle it? We asked Peter Forsyth, M.D., chair of the Department of Neuro-Oncology at Moffitt Cancer Center, for his take on where treatment is now and where he sees it going in the future.
How can doctors best help patients who are facing a brain cancer diagnosis?
We all have to cooperate and work together as a team. Bring the clinic into the lab and the lab into the clinic. That means things like interrogating tissue, doing things like biopsies or studying fluids to really determine if drugs are getting there. And if they are getting there, are they getting there at the correct concentrations? And if they are there with good concentrations, are they having the effect you want them to? We look for things like resistance and matching a tumor’s profile to a particular drug.
Some of the other things we can do at Moffitt in particular is that we can think differently about these problems and involve mathematical oncology (“the math” guys) and the evolutionary biology group. I think this brings a new perspective that many people don’t think about at all. New ways of looking at things lead to new ideas.
Does personalized medicine play into that?
There have been some very exciting developments of new targets and new drugs in brain cancer. The targets are uncommon so far, and only 3% to 5% of people with brain cancers have them. But it’s like winning the lottery. If you are one of those people with a target in your tumor for which there is an effective drug, it makes a big difference.
The drugs can make tumors shrink and go away for a long time. In many people it is pretty impressive. There are just a lot of interesting new approaches, new drugs and new discoveries. We need to embrace these and keep the excitement going. There is real hope in the clinic every day.
What has the treatment trend been? Where is it going?
I think targeted therapies are having a resurgence recently and there are new drugs being developed every month it seems. The immunotherapies took a little bit of a hit recently because there was a huge trial in glioblastoma patients that was negative. But that doesn’t matter at all because that was only one drug and essentially a “first try.” There are hundreds of drugs and hundreds of approaches in immunotherapy. Immunotherapy will stay at the forefront for a long time as we understand how to turn on the immune system and focus it on the brain. Really the personalized medicine approach is key and understanding who will benefit from these new treatments and who should avoid them if they are going to have a bad side effect. Overall it’s pretty inspiring, the thought and creative energy of people working in the brain tumor field is amazing. As a group I think we’re going to make a big difference in this.
Have there been significant advances on the surgical side?
Surgeries have evolved over the past few years. Michael Vogelbaum, M.D., Ph.D., (program leader of Neuro-Oncology and chief of Neurosurgery at Moffitt) is a leader in the field. He has a program in drug delivery that delivers drugs directly into tumors to overcome the issues with the blood-brain barrier to deliver new treatments. Things have changed surgically in terms of imaging, detecting tumor cells in the operating room and making sure surgeons get all the tumor cells without affecting the normal cells of the brain. He also emphasizes evidence-based neurosurgical care where we do trials to understand if one approach is better than another. We want to provide the best care driven by data so you know you’re doing the best thing for the patient.
So there are huge advances in neurosurgical approaches and working as part of a team. It’s very inspiring and very cool.
Is cellular immunotherapy something that we will see in the near future?
There are a couple of different groups that have looked at CAR T cell therapy in brain tumors, but there have been problems with those. Maybe they used the wrong targets. There are some serious side effects systemically for lymphoma and leukemia patients that can generally be managed quite well. Depending on the particular CAR T, maybe half of patients can get neurological toxicity. Some people have been a little reluctant to introduce these into brain tumor patients, but I’m sure this is coming.
With checkpoint inhibitors there was a negative study early on. But again, that was just one drug. There are all sorts of drugs and we have to learn how to combine them effectively. So I think there is a huge benefit there. With melanoma brain metastases and checkpoint inhibitors, the results have been very impressive and patients can have long disease-free survival. If a patient can get over the first three or four months of therapy, they can live a long time. We just don’t know how long yet. It’s completely different than the outlook for melanoma brain metastases patients five years ago when this was a rapidly fatal disease. And these patients aren’t just “surviving,” they are thriving! They’re getting normal again, traveling and having fun. They are doing things they want to do and it’s truly inspiring.
There’s a lot of excitement for all of the advances that are just on the horizon, and a lot of people are working on this and I think it’s very exciting. There’s a lot of hope, and I’m pretty pumped up about working in such an exciting field at such a great place.