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Medulloblastomas are tumors of the cerebellum that mainly affect children and adolescents. Today, two-thirds of patients can be cured by a combination of surgery, radiation and chemotherapy. However, treatment often has significant long-term consequences. "Due to intensive therapy, the brain, which is still developing, is often irreversibly damaged," says Prof. Dr. med. Torsten Pietsch of the Institute of Neuropathology of the University of Bonn. "As sequelae, surviving patients often suffer from impaired cognitive performance throughout life."
It is known today that medulloblastoma is a group of different cancers. Nearly 20 years ago, a rare nodular variant was discovered that particularly affects infants. These tumors generally respond so well to drug therapy that no additional radiotherapy is needed. Meanwhile, a group of older children has been identified, which also has a very good prognosis. This can also reduce the intensity of the therapy. It represents about 10% of all people affected. "With the big rest – after all, more than 80% – it was previously impossible to predict the response to treatment," says Pietsch. "Therefore, in these cases, intensive radiotherapy and chemotherapy are essential in the current state of research."
However, this could change in the future: researchers involved in the study have identified a new variant of the disease that presents particularly good chances of healing. To do this, they examined the tumors of participants in a study on the treatment of medulloblastoma in Europe.
"We have seen characteristic changes in the number of chromosomes in some of the tumors," says Dr. Tobias Goschzik of the Institute of Neuropathology. Human cells usually contain 23 chromosomes, each doubling. Together, they contain complete genetic information. In tumor cells, one of them, chromosome 7, often appeared in triplicate. Of the other two – chromosomes 8 and 11 – there was often only one version.
Almost 100% chance of healing
The interesting thing about it: patients with these chromosomal abnormalities could be cured with the help of a standard treatment at nearly 100%. In contrast, the chances of recovery were only 64% for the remaining victims. "It may mean that you can treat patients with this type of medulloblastoma less aggressively," says Pietsch. "However, if this is true, it must first be demonstrated in treatment studies."
In the study, tumors of 136 children and adolescents were examined. Excluded are those who suffer from a particularly aggressive form of the disease. "If we extrapolate our numbers to all patients, we badume that about 20% are suffering from the variant we have identified," Pietsch said. The results have since been verified with a second group of patients from Newcastle English.
In a next step, scientists now want to investigate why tumors with a modified number of chromosomes respond so much better to therapy. In the long run, this could also lead to new targeted treatment options. One point is particularly interesting in this context: there are also other cancers in the child badociated with changes in the number of chromosomes. This includes, for example, a specific form of leukemia. And these too can be treated particularly promising.
The Brain Tumor Reference Center (HTRZ) of the German Society of Neuropathology has been based at the Institute of Neuropathology at the University of Bonn since 1994. HTRZ employees have been working for years on the clbadification of medulloblastomas and 39, other brain tumors by WHO.
scientific contact:
Teacher. Dr. Torsten Pietsch
Institute of Neuropathology
University of Bonn
Reference Center on Brain Tumors
Phone 0228 / 287-16602
E-mail: [email protected]
Original publication:
Tobias Goschzik, Edward Schwalbe, Debbie Hicks, Amanda Smith, Anja zur Muehlen, Dominic Figarella-Branger, Francois Doz, Stefan Rutkowski, Birgitta Lannering, Torsten Pietsch, Steven Clifford: Prognostic effect of signatures of whole chromosomal aberrations in non -TNO at Standard Risk / Non-SHH Medulloblastoma: Retrospective Molecular Analysis of the HIT-SIOP-PNET4 Clinical Trial. Lancet Oncology 2018, DOI: 10.1016 / S1470-2045 (18) 30532-1
idw 2018/11
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