Differential diagnosis
Medulloblastomas have to be differentiated from similar small cell embryonic tumors such as neuroblastomas, ependymoblastomas, pinealomas and tumors of the lymphatic tissue (lymphomas).
Therapy
The therapy consists of the most radical possible surgical removal of the tumor and the subsequent high-dose irradiation with 40 Gray with direct irradiation of the posterior fossa and the entire cerebrospinal fluid space (neuro axis). Not every tumor responds well to irradiation. Medulloblastomas, however, are tumors that are sensitive to radiation.
This means that the tumor cells are effectively killed by radiation. Since brain tumors often grow infiltratively into the surrounding nervous tissue, they can usually not be completely removed during surgery. It is only through radiation that remaining tumor cells are killed.Therefore, the prognosis for the patient is significantly improved by the radiation.
Since medulloblastoma often leads to the formation of daughter tumors in the entire central nervous system, the decision is usually made to irradiate the brain and spinal cord over a large area. Since medulloblastomas are very sensitive to radiation, a cure can be achieved in over 50% of cases. The combination of postoperative radiation with chemotherapy has shown positive results in terms of recurrence and survival rates and may even be curative. In chemotherapy, cell division inhibiting agents (cytostatics) are administered to the group of nitrosureas such as CCNU, but also vincristine and cisplatin. In children under 3 years of age, chemotherapy can delay the time of irradiation and in some cases even replace irradiation
Prophylaxis
Since the risk factors and triggers for the development of glioblastomas are largely unknown, there are also no recommendations for prevention. In general, it is recommended to avoid unnecessary radiation (especially in children) as well as contact with carcinogenic chemicals and pollutants, even though environmental factors play only a minor role in the development of brain tumors.
Prognosis
Patients with a complete resection of the tumor, lacking detection of CSF metastases and lacking detection of tumor cells in the CSF (negative CSF cytology), who have received combined radiation and chemotherapy postoperatively, have a relatively good prognosis despite the high malignancy of medulloblastomas. However, a recurrence or growth (relapse) of the tumor is frequent. Medulloblastomas that only manifest themselves in adulthood have a better prognosis and metastasize less frequently.
Untreated, the survival time is only short. A recurrence is the recurrence of a tumor after an originally successful treatment. Although the tumor has been completely destroyed by surgery, radiation and chemotherapy, individual tumor cells can survive and regrow.
If the tumor reappears at the same location, this is called a local recurrence. About one third of children suffer this fate. Especially small children, whose tumor has already formed daughter tumors at the time of diagnosis, have a very high recurrence rate.
Older children (over 4 years) without metastases have a low recurrence rate and therefore a better prognosis. A recurrence usually occurs within the first two years after initial therapy. The two-year survival rate averages 70%, the five-year survival rate is about 50-70%, the ten-year survival rate is 50%, and even after 10 years about one third of patients are still recurrence-free.
