Brain Matters April 2016

Podcast: Download (Duration: 6:37 — 9.1MB)

Subscribe: RSS

Program Notes

0:14 Large experience here at Hopkins
1:15 Contrast agents accumulates in certain places
2:15 Difference dramatic
3:05 Astrocytoma is an infiltrative tumor
4:07 Not always that a grade 3 becomes a grade 4
5:08 Grade 4 can be so infiltrative that it needs diffuse therapy
6:05 Don’t create a new neurological problem
6:37 End

Transcript

Elizabeth Tracey: Welcome to this month's Brain Matters. I'm Elizabeth Tracey.

John Weingart: I'm John Weingart, Professor of Neurosurgery at Johns Hopkins Hospital.

Elizabeth Tracey: John, you picked something really interesting with a large number of patients in it for this month. Let's talk about it.

John Weingart: Elizabeth, this is a large experience at one institution. It happens to be our institution here at Johns Hopkins, but it involves really a small group of surgeons. One of the issues that exists with the high-grade astrocytoma is what is the true benefit of resection? It does give a diagnosis, but there's been some difficulty over the years in finding good evidence that better surgery results in better outcomes for patients. And so this was a retrospective study trying to get at that particular information. We felt that given that it was a small group of people that was doing the surgery, using the same technology, carrying out the surgery, post-operative care, post-surgery treatment in a very similar way, that we could hopefully get at that piece of information. So this This is a study that involves 1,200 patients. We looked at the post-operative MRI scan to assess how much residual enhancement was present on the MRI scan. And enhancement is where, when the contrast agent is given to the person during the MRI scan, the contrast agent accumulates in certain portions of the tumor. And that's the portion of the tumor that we want to remove at surgery. So we graded the quality of the resection by whether all of the enhancement was gone, compared to patients that had a thin rim enhancement to those that had bulky or nodular enhancement remaining. And we looked at patients that had had first-time surgery for what we call a grade 4 glioma, first-time surgery for a grade 3 glioma, and patients that had second surgery for a grade 4 glioma. And the bottom line was that for people with a grade 4 glioma, that if they had gross total resection or removal of all of the enhancing disease, their median survival was 13%. months. If they had just a small bit of enhancement left, then their median survival was 11 months versus eight months if there was still bulky disease left. If it was a second surgery, again, it was a similar type of benefit. For the grade threes, the difference was even more dramatic. The goal of getting an aggressive resection has to be taken in context with it being done safely. There are other secondary benefits to a resection that include better quality of life, less need for steroids, and a better, more accurate diagnosis. This clearly is a strong piece of evidence that supports people having a more aggressive resection as long as it's done safely.

Elizabeth Tracey: It seems curious to me that this was ever a question. And certainly there are plenty of examples in medicine where a priori, we have certain ideas about how things are going to turn out. And then when they're subsequently tested, we find out, oops, guess what? It's not exactly the outcome that I predicted. What was the basis of questioning with regard to search resection of tumors, of astrocytoma specifically.

John Weingart: Well, the astrocytoma is an infiltrator tumor, so there's no capsule, there's no edge, so there's always tumor remaining. And ultimately, how that person does is dependent on what happens to those remaining tumor cells. Before MRI scans, it was hard to know how much was really removed. A variety of tools over the years have been developed that have led to improved ability to resect things. We have interoperative MRI scan that can be used during surgery to assess the degree of resection. And then we have neuronavigation, which is like a GPS for brain surgery tool in terms of tabulating data and saying, yes, this group really had complete resection. You can now do that, whereas pre-MRI scan, it was really up to the surgeon's opinion about whether that had occurred.

Elizabeth Tracey: I'm really persuaded here by the difference between the stage 3 disease outcomes and the stage 4 disease outcomes. If you could create a tool that would help you to identify people earlier, that certainly would improve outcomes, right?

John Weingart: It's not always that a grade 3 becomes a grade 4. The grade 3 tumor can become a grade 4, but it tends to present as a grade 3 tumor. Oftentimes it's in a little younger population, so they're sort of in between the very low grade and the higher grade astrocytoma, their frequency is much less than the grade 4. But it highlights that in terms of the value of resection, the one thing about a grade 3 that probably is different than a grade 4 is that it's much less infiltrative. So therefore, the concept or hypothesis that if you can reduce the number of tumor cells to the smallest amount, that surgery itself can have an impact on the natural history of the disease, that or concept, the grade three data from this paper is proof in principle that that statement is true. For some grade four gliomas, it can be that it's so diffuse and infiltrative that surgery is not removing a significant amount of cells to really make a difference. And that's a segment of the disease that a group of patients that have this disease that needs another therapy that more diffusely can attack that, whether that be immunotherapy therapy or some other systemic therapy that gets to all areas, in addition to the standard treatment of radiation, will ultimately be required to impact those people that have a much more infiltrative process as opposed to one that's more focal.

Elizabeth Tracey: Here's my last question. This data is kind of old, and so what would you say about today's outcomes relative to resection?

John Weingart: The goal of, at least here at Hopkins, in treating people with this problem, whether it's initial surgery or recurrent surgery, is complete resection. And there are times when we use tools that we didn't have then to accomplish that, includes the intraop MRI scan. functional imaging we use to be a little more aggressive with resection. Again, all tempered with not creating a new neurological problem for the person because that does detract from how they do in terms of tumor control, but also obviously in terms of quality of life. This has highlighted our approach here for the last 20 years in terms of our goals at surgery. We're able to achieve complete resection of the most abnormal portion of the tumor.

Elizabeth Tracey: Excellent. Thank you so very much.

John Weingart: Thank you.