Discussing the World Health Organization's New Brain Tumor Classification
The World Health Organization (WHO) reclassified some types of brain cancers, giving a clearer outline on how to treat them.
BY Greg Kennelty
PUBLISHED January 13, 2017
Treatment for diffuse gliomas and embryonal tumors, among other cancer types, have become clearer thanks to the World Health Organization’s (WHO) recently revised tumor classifications.
In an interview with CURE, Arie Perry, M.D., chief of neuropathology at UCSF in San Francisco, California, discusses what oncologists should be aware of when diagnosing patients after these reclassifications, how it could change pathology, as well as a discussion on hereditary tumors.
Can you tell use a little about the changes in WHO classifications?
The biggest classification changes are occurring in the diffuse gliomas, which is a big category mostly in adults, and embryonal tumors, which is mainly occurring in pediatric patients.
What should the oncology community be aware of with this change in classification?
There are some new groups that are more accurately defined by molecular criteria and that if their pathologists are not doing the assays required to make those distinctions they probably need to have a chat with them or make sure that they send it out to laboratories where they are able to do that. It has prognostic significance and in some cases, will probably change the management of the patient depending on the molecular results that are obtained.
So you mentioned that it could change pathology. What is being done with the pathology?
Yes, I think you know a lot of it is prognostic, so it may not necessarily change the therapeutic approach, but in some cases, if it’s a dramatic change in terms of expected survival, for example, it may impact how they approach the management of the patient. In the embryonal tumors, the pediatric cases in particular, I think there’s some really dramatic shifts in terms of either lesser aggressive therapies or more aggressive therapies depending on some of the findings.
Initially, in some of those patients, especially in the pediatric cases, there are actually germline mutations that we identify so it actually has implication for the entire family, in terms of hereditary tumor syndromes. So other family members may also be at increased risk of developing certain tumor types.
Can you talk a little more about the hereditary tumors?
In medulloblastoma, for example, there are several tumor predisposition syndromes that are associated with some of the youngest patients that get those. One is called Gorlin syndrome, and the patients may get some other things like skin cancers or basal cell carcinomas. It also may impact whether or not they’re able to get radiation therapy, because actually it’s contraindicated in many of those patients. If you give radiation, a lot of times they’ll get skin tumors where the radiation is given.
There’s another one called Li–Fraumeni syndrome that is due to p53 mutations, and other family members may be predisposed to get colon cancer, or breast cancer, or sarcomas, which are malignancies in the soft tissues in the bodies.
What should we be looking for in the future with the how how tumors are classified, and what it means?
I think more and more we’re adding genetics into our classification scheme and probably more and more in the future we’ll also be using genomics and rather than looking at one gene at a time, or one biomarker at a time, we’ll actually be looking at the entire genome or at least cancer-associated genes within the genome. We’re already starting to do that, especially within the pediatric cases, but a subset of the adult cases as well, and so sometimes we’ll find mutations or genetic alterations that aren’t necessarily reported in that tumor type, but for which there are targeted therapies, so it may shift the way that the oncologists then decided to treat that patient.
What do you think are the key takeaways?
I think the takeaway is that things are changing in a good way in terms of it becoming a little more complicated and more technical. But it used to be somewhat subjective and there were differences between one pathologist diagnosis and another, and I think the more we define things objectively with molecular markers, the less that’s going to occur and the more confidence the oncologists will have that the diagnosis is accurate, and more importantly perhaps will guide the way they treat individual patients, so it won’t necessarily be that everyone with the identical diagnosis will be treated the same way because there may be other differences in the molecular makeup of that tumor.
What does the multidisciplinary approach look like at the tumor board?
It’s the same way it has been for many years, although you know everyone’s area is becoming more complicated. I think it’s even more important that we get together once a week at least to go over patients and the intricacies of the pathology, the diagnosis, changes in radiology, what protocols may have just opened up, what’s available for certain patients, what molecular studies have shown us that may be expected or unexpected in that particular patient and then what’s the best approach for this patient going forward.