Neurosurgical Oncology – Long-term Prognosis of Patients with IDH1 Mutant Tumors

Dr. Daniel Cahill, MD, PhD, who is presenting at the 2019 American Association of Neurological Surgeons (AANS) Scientific Sessions, discusses the latest techniques that are helping surgeons at Massachusetts General Hospital to make substantial impacts on long-term prognosis of individuals with IDH1 mutant tumors in patients who are often in their 20s or 30s.

As a neurosurgeon-scientist, Dr. Cahill’s clinical practice is focused on the care of brain tumor patients, improving clinical trials of therapy for these patients, and training neurosurgical residents in the diagnosis and treatment of these cancers.  


Neal Howard: Hello and welcome. I’m your host Neal Howard here on Health Professional Radio, thanks for joining us once again. We have in studio with us this morning Dr. Daniel Cahill, he’s presenting at the 2019 American Association of Neurological Surgeons Scientific Sessions and he’s joining us on the program to talk about some of the latest techniques that are being used to help surgeons at Mass General make substantial impacts on long-term prognosis of individuals with IDH1 mutant tumors. Thanks for joining us on the program today Dr. Cahill.

Dr. Daniel Cahill: Thank you very much for having me.

Neal:  Now I know that you’re a neurosurgeon scientist. Give us a bit of background about yourself and talk about this IDH1mutant tumor.

Dr Cahill: Sure, absolutely. So I practice at Mass General as you mentioned and my real focus is on patients who have primary brain tumors and over the last 10 years, there’s been a major revolution in recognizing patients who have these tumors, being able to categorize them appropriately based on what diagnosis they have, what type of tumor they have. And in 2016,  there has been a reclassification of the tumors that includes this molecular status or IDH status. There are two genes, IDH1 and IDH2, which categorize patient to have a real benefit from having aggressive surgery to help them live longer with that treatment and we can identify them now that we know about these molecular subtypes.

Neal: So who’s at risk of developing these specific types of tumors?

Dr Cahill: That’s a good question. So we typically find these tumors in patients who range in age from about in their mid 20s to about their mid 40s, although I have seen a very wide range of patients, in my own personal practice I’ve had patients as young as 11 years old all the way up to 89 so there is a broad range. However it tends to be young adults, people who are entering the prime of their life, of their early working years, early family years, just getting married or starting to have children and so this is a major impact to get a diagnosis like this. Odd that they have a brain tumor at that age and it is very scary and one of the things that’s really very positive about the recent findings is that we can intervene in a way that really promotes or maximizes the chance for long-term survival in these patients. Patients really do seem to have a dramatic extension of survival in association with aggressive surgery in this subgroup.

Neal: What was the traditional outcome? What was done and what was the longevity expectation there?

Dr Cahill: Right. The best we can tell what happened in the past is based on historical data which predates our knowledge about the IDH mutation which was only discovered in 2008. So when we looked in clinical series of patients prior to that time, they were mixed. They were heterogeneous and it was hard for us to pick out the specific subgroup of patients so basically all patients would get sort of standard therapy which was a surgical procedure than radiation chemotherapy and what we can recognize now from looking at sort of selected groups or cohorts that just have the IDH mutation is that the type of surgery has to be very specific so it’s some resection of the standard resection but then additional amounts of resection around the edges of the tumor and what that means typically or in many cases is as you do that first surgery and then the patient find out they have the IDH mutant tumor they often have to think about having a second surgery or what we refer to as a completion surgery so that they can get to the best starting point before they then start follow up with neuro-oncology and then consideration of the timing of other treatments.

Neal: So as far as recovering from the initial surgery, has that been reduced recently?

Dr Cahill: Yeah, what I would say is that these patients have a lot of time to consider their options so what will happen is they have their initial surgery and in that first month or so of recovery, they find out that they have an IDH mutant tumor and we can then reassess whether a new viewpoint or a new …  and in the next few months they … could plan a second surgery after things have re-normalize from the first procedure. These patients tend to do extremely well in terms of neurologic outcome, they’re typically functional back to work and back to their family lives and everything like that very, very soon after the initial surgery or the initial two surgeries,  whatever anybody needs.

Neal: And as far as recurrence of the problems, are we talking complete recovery in say living into their 70s or is the 50s once the diagnosis is made and the treatment is rendered, are we talking 50s, early 50s, 50s for survival?

Dr Cahill: Yeah, that’s a key question so we’re really trying to learn as much as we can about that. So there are patients who have progressive disease and this is a subset of the subset so as a percentage of patients who are IDH mutant, the vast majority of patients do very well. There is a subset that has progressive disease and we’re trying to understand how patients switch or have this more accelerated growth rate and what we can do to stop it. So it is difficult  for us to know really if we do the optimal treatment what is the expected survival. We know it’s very long but we don’t know what it is that then causes certain patients to switch into a more accelerated growth rate. Those patients then have a very difficult course and they actually have a fatal course and they switch to an accelerated rate, but as I said that’s a percentage of the patient so we’re learning a lot about that – that’s our current focus of research.

Neal: Where can we go online and get some more information about this mutant tumor and learn some more about what was going on in the past and talk more about, learn more about the sessions that you were involved in?

Dr Cahill: Right. So I would say that you know there is very good information at both the National Brain Tumor Society website and the ABTA website and then also on our website at Mass General. The brain tumor center here is very comprehensive and you can learn a lot of information about this new way of categorizing tumors, the WHO 2016 diagnostic criteria and and how that has impacted how we approach patients and in their initial phases of diagnosis and how we make the diagnosis and then how we plan their treatments afterwards so.

Neal: Dr. Cahill,  thanks for joining us on the program this morning.

Dr Cahill: Thank you so much for having me.

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