|Year : 2023 | Volume
| Issue : 1 | Page : 1-2
Survival trends for patients with primary brain tumors worldwide: What have we learnt?
Michael Weller1, Emilie Le Rhun2
1 Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
2 Department of Neurology, University Hospital and University of Zurich; Department of Neurosurgery, University Hospital and University of Zurich, Zurich, Switzerland
|Date of Submission||10-Jan-2023|
|Date of Decision||19-Jan-2023|
|Date of Acceptance||07-Feb-2023|
|Date of Web Publication||30-Mar-2023|
Prof. Michael Weller
Department of Neurology, University Hospital and University of Zurich, Frauenklinikstrasse 268 091 Zurich
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Weller M, Le Rhun E. Survival trends for patients with primary brain tumors worldwide: What have we learnt?. Glioma 2023;6:1-2
|How to cite this URL:|
Weller M, Le Rhun E. Survival trends for patients with primary brain tumors worldwide: What have we learnt?. Glioma [serial online] 2023 [cited 2023 Nov 29];6:1-2. Available from: http://www.jglioma.com/text.asp?2023/6/1/1/372821
Neuro-oncology, notably the field of gliomas, has undergone major changes over the last decades, notably with regard to how we classify and diagnose gliomas. This has resulted in updates of the WHO classification in 2007, 2016, and 2021. A recent publication by Girardi et al. published in a Neuro-oncology reported global survival trends for the major groups of gliomas in adulthood, astrocytomas, oligodendrogliomas, and glioblastomas, based on the analysis of 556,237 adult patients diagnosed in 59 countries from 2000 to 2014. The authors conclude that survival improvements have been “extensive” and that some countries still lag behind. This publication has resulted in discussions, notably on the country-specific data, in several countries.
For China, it had been noteworthy in a preceding publication of Girardi et al. that less than 10% of tumors were diagnosed with glioblastoma but that 52% of tumors were “unspecified tumors.” For the 5-year survival rates reported in 2022, China was average for astrocytomas and oligodendroglioma, whereas survival was among the highest for glioblastoma.
Does that truly inform the quality of diagnosis and care in China? Is this merely reflecting the fact that pathologists and oncologists in China diagnose glioblastoma less frequently and that most tumors considered glioblastoma elsewhere ended up in the category of “unspecified tumors” in China? Are we sure that the small group of glioblastomas diagnosed in China are the same tumors as more than 50% of glioblastomas diagnosed in the US and in most European countries? Or do we believe that treatment and care are better in China than in most other parts of the world?
Our caveat is that such data are very different to interpret because gliomas are not a simple uniform disease category and because diagnostic and therapeutic approaches have evolved significantly over time, but still vary widely worldwide. For instance, in the first population-based Zurich cantonal registry study, nonbiopsied patients were still included, whereas today, such patients would not enter into the cancer registry or would be excluded from reporting.
It also seems premature and an overinterpretation of the data to conclude that the introduction of temozolomide alone accounted for the major improvement in survival noted in some countries. A more balanced view would be to also take into consideration that radiotherapy, while potentially not being more active than 20 years ago, today is much more focused and likely to cause much less long-term toxicity, in turn, will no longer render patients less eligible for salvage treatments and thereby contribute to inferior survival. We also do think that the quality of neurosurgery is essential and that it varies significantly across the countries included in this study. To what degree the extent of resection contributes to the outcome remains controversial, yet, our personal view is that the role of surgery in shaping survival curves is likely more prominent for astrocytoma and oligodendroglioma than for glioblastoma. The improved access to neuroimaging and to supportive and palliative care interventions may also have contributed to improved survival in some countries.
The standardized approach to evaluating the data included in the study cannot overcome the inherent limitations of the source data that are likely to be incomplete and of heterogeneous quality. Why the increase in survival should not be visible in glioblastoma patients aged 40 or less remains unclear and enforces the view that the data should not be overinterpreted.
Conversely, as indicated above, it is also noteworthy that the rate of brain tumors coded as nonspecific histology varied significantly: it was 64% of all brain tumor diagnoses in China which appears high.
In conclusion, the exchange of high-quality data across countries in a global registry would certainly contribute to our understanding of gliomas as a disease category in general. Molecular analyses have so far not provided evidence that gliomas differ very much genetically worldwide; in contrast, the tumors appear strikingly similar regarding the major molecular genetic pathways involved. Treatment algorithms will continue to differ and are largely driven by the financial resources available for the treatment and care of patients. We should remain modest with regard to recognizing that, at least for glioblastoma, our interventions do not have a major impact, the cure does not exist, and long-term survival remains the exception. Meanwhile, our patient populations worldwide would undoubtedly benefit from more structured pathways along the disease trajectory, including adherence to the WHO classification as feasible, access to specialized neurosurgery and adequate radiation oncology facilities, access to alkylating agents, and systematic recognition and management of complications during standardized follow-up.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
Editor note: MW is an Editorial Board member of Glioma. He was blinded from reviewing or making decisions on the manuscript. The article was subject to the journal's standard procedures, with peer review handled independently of this Editorial Board member and their research groups.
| References|| |
Girardi F, Matz M, Stiller C, You H, Marcos Gragera R, Valkov MY, et al.
Global survival trends for brain tumors, by histology: Analysis of individual records for 556,237 adults diagnosed in 59 countries during 2000-2014 (CONCORD-3). Neuro Oncol 2022. doi: 10.1093/neuonc/noac217.
Girardi F, Rous B, Stiller CA, Gatta G, Fersht N, Storm HH, et al.
The histology of brain tumors for 67 331 children and 671 085 adults diagnosed in 60 countries during 2000-2014: A global, population-based study (CONCORD-3). Neuro Oncol 2021;23:1765-76.
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Glioblastoma in the Canton of Zurich, Switzerland revisited: 2005 to 2009. Cancer 2016;122:2206-15.
Roth P, Pace A, Le Rhun E, Weller M, Ay C, Cohen-Jonathan Moyal E, et al.
Neurological and vascular complications of primary and secondary brain tumours: EANO-ESMO Clinical Practice Guidelines for prophylaxis, diagnosis, treatment and follow-up. Ann Oncol 2021;32:171-82.