Updates in the Management of Primary CNS Malignancies
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Updates on CNS Malignancies in the Era of Genomic Medicine
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Updates in the Management of Primary CNS Malignancies
- 1. UPDATES ON CNS MALIGNANCIES IN THE ERA OF GENOMIC MEDICINE Mary Ondinee Manalo Igot, MD Medical Oncology – Neuro Oncology The Medical City October 2016
- 2. Outline • Something old • Review of nomenclature of CNS tumors • Mutations and molecular markers of CNS tumors • Something new • Lower grade gliomas LrGGs as one entity differentiated by molecular subtype • 2016 WHO Classification of CNS tumors • Something borrowed • Temozolomide for LrGGs • Immunotherapy for glioblastoma • Something blue • Disappointments in glioblastoma • Novel treatment for glioblastoma
- 4. History of histological typing of CNS tumors • 1979: edited by Zulch, purely histologic made into the First Edition • 1993: edited by Kleihues, IHC was introduced, made into the Second Edition • 2000: edited by Kleihues and Cavenee, attempted genetic profiles to be described, recognized by the WHO and was made into the Third Edition
- 6. WHO Classification of Glioma by Histology Louis DN, et al. Acta Neuropathol 2007 114(2):97. High grade gliomas Low grade gliomas Histology guided treatment Interme- diate grade gliomas
- 7. Top CNS molecular markers in the past decade • MGMT promoter methylation • 1p/19q co-deletion • IDH1 and IDH2 mutation • Others: • TP53 • ATRX • pTERT • CIC • FUBP1 • NOTCH1
- 8. MGMT promoter methylation • MGMT aids in the repair of tumour DNA that has been damaged by chemotherapy. • Patients with low MGMT activity (via methylation of MGMT promoter) will be expected to have better response to alkylating agents such as temozolomide. • Methylation of MGMT promoter gene is present in about 30% to 45% of glioblastoma patients. Neuro Oncol (2010) 12 (2): 116-121.
- 9. IDH 1/2 mutations • Present in 50-80% of WHO grades II and III tumors and in secondary glioblastomas Curr Neurol Neurosci Rep. 2013
- 10. IDH 1/2 mutations • Isocitrate dehydrogenases, encoded by the IDH1 and IDH2 genes, catalyze the reduction of NADP+ to NADPH in the brain • IDH-mutated tumors experience superior survival compared with IDH-wild type of the same histologic grade Curr Neurol Neurosci Rep. 2013
- 11. LOH of 1p/19q • Better prognosis if 1p/19q is codeleted in patients with oligodendroglioma / component • Predictive biomarker of chemotherapy response • Improved survival after chemoRT, compared with RT alone Neuro Oncol. 2014 Jan;16(1):103-12.
- 12. ATRX deficiency (alpha thalassemia/mental retardation syndrome X-linked) • ATRX is a chromatin remodeling factor, which plays a crucial role in heterochromatin maintenance, particularly at telomeres. • Its dysfunction has been correlated with genomic instability and DNA replications stress, along with abnormal telomere elongation • Loss-of-function mutations in the ATRX gene is a highly recurrent molecular signature of adult diffuse astrocytoma Neuro Oncol (2014) 16 (suppl 3): iii45.
- 13. TP53 • The p53 tumor suppressor gene (TP53) is the most frequently altered gene in human cancer and is also found mutated in several types of brain tumors. • Approximately 33% of low grade infiltrating astrocytomas have mutations detected in the p53 gene on chromosome 17p. • Anaplastic astrocytomas (grade 3)-whether found in preexistent low grade astrocytomas or detected de novo-have a similar incidence of p53 mutations but, in addition, show a loss of heterozygosity on chromosome 19q in more than 40% of cases.
- 14. pTERT • Telomerase reverse transcriptase (TERT) activity is up- regulated in several types of tumors including glioblastoma (GBM). • TERT mutations occur frequently in glioblastoma (69%) and oligodendrogliomas (72%) but were less frequent in astrocytomas (24%) and oligoastrocytomas (38%). • The HR for glioma patients with TERT mutations versus wild type TERT was 1.63 (95% CI 1.35-1.98). • Recent studies show that the TERT gene is a valuable prognostic and predictive biomarker of gliomas. Acta Neuropathol. 2013 Dec;126(6):789-92. J Clin Neurosci. 2016 Apr;26:57-62.
- 15. PROBLEM: • In patients with WHO grades II and III tumors, there is a very wide variety of presentation, response to treatment and survival • Some gliomas progress to glioblastoma in a few months • Others remain stable for years • Survival varies WIDELY from 1-15 years • Some gliomas have impressive therapeutic sensitivity
- 16. SOMETHING NEW…
- 17. Definition of Terms • Lower grade glioma (LrGG): A diffusely infiltrative low- grade or intermediate-grade glioma (World Health Organization grade II or III) that arises most often in the cerebral hemispheres of adults and includes astrocytomas, oligodendrogliomas, and oligoastrocytomas. • Glioblastoma: The highest-grade (World Health Organization grade IV). It is distinguished histopatho- logically from diffuse lower-grade astrocytomas (grades II and III) by the presence of necrosis or microvascular proliferation.
- 18. • BACKGROUND: • Diffuse lower grade gliomas (LrGG) have a highly variable clinical behavior that is not adequately predicted on the basis of histology alone • METHODS: • Tumor samples from 293 adults with previously untreated LrGG were taken and exome sequencing, DNA copy profiling, mRNA sequencing, DNA methylation profiling, TERT promoter sequencing, RPPA profiling and were subjected to multiple platforms for analysis including cluster of clusters (CoC) and OncoSIgn.
- 22. Clinical outcomes accdg to histology vs molecular subtype
- 23. “The family trees have been redrawn.”
- 29. New entity • DIFFUSE MIDLINE GLIOMA, H3 K27M-mutant • Primarily occurring in children but we see more adults having it now • Diffuse growth pattern • Midline location (thalamus, brain stem, and spinal cord) • Includes tumors previously referred to as diffuse intrinsic pontine glioma (DIPG) • The identification of the mutation provides a rationale for therapies directed against (HDACs)
- 32. Temozolomide (TMZ) for LrGG • Originally indicated and was given a Category 1 recommendation for glioblastoma • The practice of giving TMZ for LrGG • Borrowed from the Stupp study • Evidence from small phase II trials with conflicting results • BUT in reality, PCV is the recommended and Category 1 recommendation J Neurooncol. 2007;82:281-288. Clin Cancer Res. 2009;15:330-337
- 33. RTOG 0424 • PURPOSE: • Phase 2 study of a high-risk low grade glioma population treated with TMZ and RT and outcomes were compared with controls. • POPULATION: • Patients with a low grade glioma with at least 3 high risk factors: 1. ≥40 yrs 2. Astrocytoma histology 3. Bihemispherical tumor 4. Pre-operative tumor diameter of ≥6 cm 5. Pre-operative neurological function deficits Int J Radiat Oncol Biol Phys. 2015 March 1; 91(3): 497–504. doi:10.1016/j.ijrobp.2014.11.012.
- 34. RTOG 0424 • RESULTS: • 129 patients • Median ffup of 4.1 yrs • 3-YEAR OS: 73.1% (95% CI: 65.3%-80.8%, p<0.01) • MEDIAN SURVIVAL TIME HAS NOT YET BEEN REACHED • 3-YEAR PFS: 59.2% • CONCLUSION: • The 3-year OS rate of 73.1% for RTOG 0424 high-risk LGG patients is higher than that reported for historical controls (P<.001) and the study-hypothesized rate of 65%.
- 36. Immunotherapy for Glioblastoma • The aggressiveness of GBM could be attributed to its ability to escape immune system surveillance • GBM express potent immunosuppressive molecules (TGF-beta, PGE2, IL-10, etc) • Specific challenges: • Lymphopenia • Resulting from temozolomide, RT • Corticosteroids usage • The brain lacks professional antigen presenting cells • Tissue access for development of vaccine
- 37. Current approaches • Regulate immune checkpoint • CTLA-4 (e.g. ipilimumab) • PD-1 (e.g. nivolumab) • Ongoing trial – Checkmate 143 (Nivolumab +/- Ipilumumab versus Bev in recurrent GBM) • Tumour Vaccines • Antigen targeting - Peptide-based (rindopepimut) • Cell based – dendritic cells (DCVax)
- 38. Immunotherapy targeting EGFRvIII • About 30% GBM express EGFRvIII • Encodes a constitutively active tyrosine receptor that enhances tumour cell growth, invasion and promote resistance to RT and chemotherapy. • Also enhances growth of neighbouring EGFRvIII-negative tumour cells via cytokine mediated IL-6 signalling or release microvesicles containing EGFRvIII which can transfer tumour-promoting activity. • Rindopepimut • EGFRvIII peptide conjugated to Keyhole Limpet Hemocyanin (KLH) • Generates a specific immune response (both cellular and humoral response) against EGFRvIII-expresssing glioma cells
- 45. Alternating Electrical Field Therapy (NovoTTF-100A) • There has been no progress in the treatment of glioblastoma in the past decade • This novel treatment delivers low-intensity, intermediate-frequency alternative electrical field to GBM via transducer arrays applied to scalp.
- 47. Randomized trial NovoTTF-1 versus standard therapy Stupp R; ASCO 2015
- 48. TTF has better survival than standard Rx Stupp R; ASCO 2015
- 49. Is TTF the new standard of care?
- 50. Is TTF the new standard of care? • Cost is prohibitive. • Treatment would cost approx USD 21,000 or roughly Php 1 million a month for the device and its maintenance alone. • However, we should not be resistant to innovation.
- 51. Another blue…
- 52. Disulfiram combined with copper for GBM
- 53. Disulfiram combined with copper for GBM
- 54. Thank you.
Editor's Notes
- This was the nomenclature that we were using since 2007 and for the past decades, the classification of brain tumors has been based largely on histology. That tumors are classified based on their microscopic similarities. On H&E stains.
- This is just a summary of the previous table showing the more common histologies. Some authors label grades I and II as Low Grade and III and IV as High Grade. Some authors describe it as Low, Intermediate and High Grade, once there was the term ANAPLASTIC, an INTERMEDIATE or GRADE 3 was assigned. There was no uniformity and histology guided treatment options.
- Over the past decade, we have seen developments with regards to using molecular markers for ANY type of cancer and these are the most significant in my opinion. Let us discuss each briefly.
- I think that this is the most famous of all. They will have a better response to alkylating agents because the enzyme is defective and will not be able to repair the tumor DNA. The mutation is not germline. Available at St. Lukes.
- In this graph, it says here that 50-80% of WHO grades II and III tumors plus the secondary glioblastomas harbor IDH mutations, with IDH 1 being more common than IDH 2.
- To orient everyone, this is the tumor mitochondria and this is its Krebs cycle. The mutation is not germline. Isocitrate dehydrogenases, encoded by the IDH1 and IDH2 genes, catalyze the reduction of NADP+ to NADPH in the brain. Accumulation of NADPH in the brain leads to: Apoptosis resistance Phosphatase inhibition Anabolic synthesis These mutant enzymes lead to conversion of a-ketoglutarate into D-2-hydroxyglutarate, an oncometabolite that drives the oncogenic activity of IDH mutations. Can do: IDH R132H antibody testing via IHC or IDH ½ mutation hotspot testing via sequencing techniques IDH-mutated tumors experience superior survival compared with IDH-wild type of the same histologic grade. Why is this? Because if your enzyme is defective, then you will not have NADPH to produce all these effects.
- In tumors of oligodendroglial lineage, the most common cytogenetic alteration consists of an unbalanced translocation that results in the fusion of the chromosomal arms of 1p and 19q, accompanied by the loss of one hybrid chromosome, which thus results in the loss of heterozygosity of 1p and 19q. These tumors have better prognoses than histologically identical tumors of the same grade that do not harbor this codeletion. Furthermore, this biomarker has been proven to be a critical predictive biomarker of chemotherapy response, and improved survival after chemoradiotherapy, compared with RT alone. Available at St Lukes.
- This is not a germline mutation. Germline mutations in ATRX do not cause cancer, but are instead associated with neurodegeneration and mental retardation. We and others recently identified loss-of-function mutations in the ATRX gene as core components of a highly recurrent molecular signature characterizing adult diffuse astrocytoma. ATRX deficiency has also been implicated in large subsets of pediatric glioma, neuroblastoma, and pancreatic neuroendocrine tumor. ATRX is a SWI/SNF chromatin remodeling factor, which appears to play a crucial role in heterochromatin maintenance, particularly at telomeres. Its dysfunction has been correlated with genomic instability and DNA replications stress, along with abnormal telomere elongation. ATRX is lost in virtually all IDH-mutant gliomas without 1p/19q codeletion (primarily astrocytomas), but was universally maintained in IDH-wild type tumors (primarily glioblastomas), and 1p/19q co-deleted tumors (oligodendrogliomas). Interestingly, we found that ATRX-mutant gliomas were not universally negative for ATRX, with some tumor cells retaining expression. This finding, which we have confirmed by deep sequencing, suggests that ATRX mutations do not confer a strong proliferative advantage per se, but instead predispose cellular subclones to transformative events downstream, perhaps through genomic destabilization and DNA copy number alteration.
- A lot of research went into finding those specific molecular abnormalities and establishing its relationship with the histology and survival of patients because reserchers and doctors in the field of neuro-oncology noted this specific problem: In patients with WHO grades II and III tumors, there is a VERY wide variety of presentation, response to treatment and survival A subset of these gliomas will progress to glioblastoma within a few months, whereas others will remain stable for years. Survival varies WIDELY from 1-15 years, sometimes even within the same histologic subtype. And some gliomas show impressive therapeutic sensitivity.
- So from hereon onwards, I will use the definition given by Cancer Genome Atlas Network in their attempt to standardize grading. Lower grade glioma (LrGG) will be defined as a diffusely infiltrative low-grade or intermediate-grade glioma (which includes World Health Organization grade II or III) that arises most often in the cerebral hemispheres of adults and includes astrocytomas, oligodendrogliomas, and oligoastrocytomas.
- On June 2015, last year, this paper came out from The Cancer Genome Atlas Research Network and it changed how we look at histological classification of gliomas. It is entitled, COMPREHENSIVE, INTEGRATIVE GENOMIC ANALYSIS OF DIFFUSE LOWER GRADE GLIOMAS. Again this was done because lower grade gliomas have a highly variable behavior that CANNOT BE PREDICTED ON THE BASIS OF HISTOLOGY ALONE. Tumor samples from 293 adults with previously untreated LrGG were taken and exome sequencing, DNA copy profiling, mRNA sequencing, DNA methylation profiling, TERT promoter sequencing, RPPA profiling and were subjected to multiple platforms for analysis including cluster of clusters (CoC) and OncoSIgn. Basically they did everything that they can to find a common denominator and subtype them molecularly.
- This is the result of their clusters of clusters analysis. From all the samples, they were able to pick up 3 groups.
- This slide shows the summary of the major molecular findings and their conclusions. Consensus clustering yielded 3 robust groups that were strongly correlated with IDH mutation and 1p19q codeletion. So the first group had an IDH mutation, and codeletion of 1p19q. It also had inactivating mutations in CIC, FUBP1 and NOTCH1. It had activating mutations in PIK3CA, PTBP and TERT. In these patients, the clinical presentation was relatively indolent and they had good response to chemotherapy. The second group also had an IDH mutation, but 1p/19q was not codeleted. It had the following inactivating mutations and their activating mutations. In these patients, the clinical presentation was intermediate. The last group are the IDH wild types, with PTEN NF1 and CDKN2A inactivating mutations and EGFR MDM4 and TERT activating mutations. These were the most aggressive of the 3 subtypes and behaved much like glioblastomas.
- In a separate paper, a commentary was given and the author labelled these three entities as MOLECULAR OLIGODENDROGLIOMA, MOLECULAR ASTROCYTOMA, and MOLECULAR GLIOBLASTOMA… even if the HISTOLOGY says otherwise.
- These were the clinical outcomes in that paper. The one on the right shows the survival by histology and the one on the left shows the survival by molecular subtypes. Here it shows that patients with a LGG histology but is an IDH wildtype behaves pretty much like a glioblastoma
- So after that paper by the Cancer Genome Atlas Research Network was published, an update was done to the 4th edition. The first update that we have since 2007, so that’s a first update in 9-10 years. They still do not want to label it as a Fifth Edition, but rather just an update. And if you would read the entire paper, it says there that THE FAMILY TREES HAVE BEEN REDRAWN.
- So how do we classify them now? In 2014, the International Society for Neuropathology established guidelines on how to incorporate molecular testing into brain tumor histologies. This current update thus breaks the century old principle of diagnosis based entirely on microscopy. For glial tumors, after the histology has been determined, IDH mutation testing should be done…….. In the 2016 CNS WHO, the diagnosis of oligoastrocytoma is strongly discouraged. Nearly all tumors with histological features suggesting both an astrocytic and an oligodendroglial component can be classified as either astrocytoma or oligodendroglioma using genetic testing [44, 48]. The diag- noses of WHO grade II oligoastrocytoma and WHO grade III anaplastic oligoastrocytoma are, therefore, assigned NOS designations, indicating that they can only be made in the absence of appropriate diagnostic molecular testing. Notably, rare cases of “true” oligoastrocytomas have been reported in the literature, with phenotypic and genotypic evidence of spatially distinct oligodendroglioma and astro- cytoma components in the same tumor [14, 49]; until fur- ther reports confirming such tumors are available for evalu- ation as part of the next WHO classification, they should be included under the provisional entities of oligoastrocytoma, NOS, or anaplastic oligoastrocytoma, NOS. In addition, in such settings, particular care should be taken to avoid mis- interpretation of regional heterogeneity due to technical problems with ancillary techniques, such as false-negative ATRX immunostaining or false-positive FISH results for 1p/19q codeletion, which can occur regionally within tissue specimens.
- In 2007, WHO grouped all tumors with astrocytic phenotype separately from those with an oligodendroglial phenotype. Now, they are grouped into just one category. What has been displaced though, were pilocytic astrocytoma, now classified into other astrocytic tumors because they harbor a different mutation.
- This compares the survival of IDH WT and IDH mutant glioblastomas.
- Lets discuss this new entity. So now, its not only GBM that has a grading of IV in terms of aggressiveness but now we also have another entity called DIFFUSE MIDLINE GLIOMA, H3 K27M-mutant
- This came out early in 2014, and I was still there in Singapore doing my fellowship and together with my mentor, we characterized the survival of patients who we think have midline gliomas.
- Presented in Best of ASCO. After this paper came out, my co-author continued the molecular characterization study.