Medulloblastoma has various stages depending upon the risk and prognosis of the disease. The treatment is defined by the stage at which the disease is diagnosed.
What Are The Stages In Medulloblastoma?
Medulloblastoma is the tumor in the brain specifically in the cerebellum and may metastasize to other parts of the brain. After the diagnosis of the disease, the doctors tend to identify the stage at which the disease is diagnosed. Thus, they are analyzing the extent of damage the disease has done to the brain. This helps the doctor in deciding the best treatment strategy. This process of identification of the stage of tumor is termed as staging. If the tumor has metastasized to other parts of the brain, it requires an aggressive therapy while the tumor which has not metastasized requires standard therapy. Different tumors have different stages. Medulloblastoma can be divided in the various stages on the basis of following factors:
- Age: If the age of the patient with medulloblastoma is less than three years at the time of diagnosis, the tumor is described as high risk tumor while the patient with tumor has an age above three years; the tumor is staged at standard risk tumor.
-
Volume Of Tumor Remained After Surgery: Volume of tumor remained after the surgery can be concluded through MRI scan or through the surgeon’s analysis. Remaining tumor after surgery also defines the stage of the disease.
- Spread Of The Disease: Staging is generally done on the basis of metastatic spread of the tumor. More the tumor metastasis; the higher the stage of tumor.
On the basis of above features, medulloblastoma has been staged in to following types:
- Standard Risk Tumor: Standard risk tumor carries the general or average risk which all the person of medulloblastoma carries. The tumor is present on the lower back of the brain and fortunately the tumor has not been metastasized to other parts of the brain. It can be completely removed form the brain as it is not metastasized to other parts of brain and spinal cord. By complete removal means the volume of the remaining tumor is less than 1.5 cm2. Generally, the surgeons remove the entire tumor to prevent the chances of recurrence. The prognosis of medulloblastoma patients having standard risk is favorable as they are having good chance of recovery.
-
High Risk Tumor: These types of tumor are having high risk of fatal consequences as they spread to other parts of the brain and spinal cord. The volume of the tumor remained after surgery is more than 1.5 cm2. There are instances, when at the initial diagnosis the tumor was in standard risk stage but may come in high risk stage as they spread in other parts of brain and spinal cord. These tumors may or may not respond well to the therapy and have relatively poor medulloblastoma prognosis as compared to standard or average risk tumor.
- Recurrent Tumor: These are another staging of the disease. These are the medulloblastoma tumors which come back after removal in initial treatment. The tumor may recur in brain, spinal cord or in cerebrospinal fluid. The process of diagnosis and treatment is repeated in cases of recurrent tumor. Continuous monitoring is required after initial treatment to stop the spread of recurrent tumors in other areas of the brain.
The extent of spread of tumor in other parts is defined by the factor “M.” It helps in determining the degree and extent of metastasis. Following are the stages of “M”:
- M0: This is the primary stage of the tumor which indicates that after the diagnosis no evidence for metastasis of the tumor is found. This indicates that the tumor is presently limited o the area of its origin.
- M1: It indicates that the tumor has been metastasized to cerebrospinal fluid.
- M2: This stage of tumor spread indicates that tumor has been spread to other parts of the brain.
- M3: This stage of tumor spread indicates that tumor has been spread to spine.
- M4: Very rarely, the medulloblastoma spread to extracranial region such as chest.
Conclusion
The stages of medulloblastoma include standard risk stage and high risk stage. The other type may be recurrent medulloblastoma. Various stages of tumor spread have been defined such as M0, M1, M2, M3, and M4.
- Packer RJ, Vezina G. Management of and prognosis with medulloblastoma: therapy at a crossroads. Arch Neurol. 2008 Feb;65(2):141-4. doi: 10.1001/archneurol.2007.43. PMID: 18268191. (Link: https://pubmed.ncbi.nlm.nih.gov/18268191/)
- Ellison DW, Kocak M, Dalton J, Megahed H, Lusher ME, Ryan SL, Zhao W, Nicholson SL, Taylor RE, Bailey S, Clifford SC. Definition of disease-risk stratification groups in childhood medulloblastoma using combined clinical, pathologic, and molecular variables. J Clin Oncol. 2011 Jul 10;29(20):1400-7. doi: 10.1200/JCO.2010.31.8861. Epub 2011 May 31. PMID: 21632505. (Link: https://pubmed.ncbi.nlm.nih.gov/21632505/)
- Taylor MD, Northcott PA, Korshunov A, et al. Molecular subgroups of medulloblastoma: the current consensus. Acta Neuropathol. 2012 Apr;123(4):465-72. doi: 10.1007/s00401-011-0922-z. Epub 2012 Jan 29. PMID: 22286351. (Link: https://pubmed.ncbi.nlm.nih.gov/22286351/)
- Gajjar A, Chintagumpala M, Ashley D, et al. Risk-adapted craniospinal radiotherapy followed by high-dose chemotherapy and stem-cell rescue in children with newly diagnosed medulloblastoma (St Jude Medulloblastoma-96): long-term results from a prospective, multicentre trial. Lancet Oncol. 2006 Oct;7(10):813-20. doi: 10.1016/S1470-2045(06)70867-1. PMID: 17012044. (Link: https://pubmed.ncbi.nlm.nih.gov/17012044/)
- Bowers DC, Gargan L, Kapur P, et al. Study of New Onset Seizures among Children with Medulloblastoma Treated on a Uniform Chemotherapy Regimen. Pediatr Blood Cancer. 2016 Oct;63(10):1779-85. doi: 10.1002/pbc.26095. Epub 2016 Jun 7. PMID: 27273703. (Link: https://pubmed.ncbi.nlm.nih.gov/27273703/)
Also Read:
