Develop a new staging system for brain tumors where the TNM staging system is not applicable

This article is from NEJM Journal Watch Developing an Imaging-Based Staging System for Brain Tumors.
Comment on the development of imaging-based brain tumor staging system.
Author: Roy E.
Strowd, III, MD.
The new imaging-based staging system is predictable The survival rate of glioma patients can guide the future brain tumor classification system
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The TNM (tumor primary tumor, lymph node, metastasis) staging system describes the anatomical scope of cancer and has been used for solid tumors since the 1940s (Cancer Prev Control 1998; 2:262)
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However, the TNM staging system is not suitable for central nervous system (CNS) tumors
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Small tumors in the functional cortex cause high morbidity and mortality, the brain lacks a typical lymphatic system, and metastatic disease is extremely rare (Cancer Prev Control 1998; 2:262 and Neuro Oncol 2021; 23:1231)
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With the advancement of imaging technology, radiomics helps define spatial phenotypes, determine growth patterns, and develop imaging-based staging systems
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In this study, the authors evaluated the MRI data of 1,000 consecutive patients newly diagnosed with primary or metastatic brain tumors
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Of these patients, 66% had neuroepithelial tumors, 30% had brain metastases, 78% received radiotherapy, 68% received chemotherapy, and 81% received resection
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The author defined the anatomical phenotype (pilocytic astrocytoma of the hypothalamus, medulloblastoma of the cerebellum, and CNS lymphoma of the midbrain)
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They observed different growth patterns and related outcomes
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Patients with gliomas in contact with the ventricles have the lowest survival rate
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The survival rate follows a biological gradient, that is, a more serious imaging model is associated with a poor outcome
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Based on these findings, the researchers developed a non-invasive anatomical staging system: stage III: invasion of the corpus callosum or internal capsule
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Stage II: Multiple ventricle segments or diffuse ventricle/subependymal corpus callosum spread
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Stage I: No features of stage II or stage III
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Commentary on molecular diagnostics has completely changed the classification of CNS tumors (Neuro Oncol 2021; 23:123)
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For patients with glioma, comprehensive diagnosis includes histological and molecular data
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So far, no classification system has included anatomical phenotypes
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These researchers used extremely large-scale, robust and well-defined data sets to develop a new anatomical staging system that can predict patient survival
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Although these findings are thought-provoking and can put forward hypotheses, they cannot be translated into clinical practice in a short period of time
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The data set does not include molecular level classification
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The proportion of patients receiving treatment in the trial is about 80%, which raises questions about whether the results reflect the outcome of all patients
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This research is the first step in the development of future models, but it still needs to incorporate molecular-level tumor analysis in order to translate it into clinical practice
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Commented articles Akeret K et al.
Anatomical phenotyping and staging of brain tumours.
Brain 2021 Sep 23; [e-pub].
(https://doi.
org/10.
1093/brain/awab352) NEJM journals collection NEJM journals collection (NEJM Journal Watch) is published by NEJM Group.
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