the most common type of brain tumor, often benign, but aggressive in a small percentage of cases. How to know when? If, in addition to the microscope, genetic profiling is used, more precise information is obtained
It is not easy to determine whether a meningioma, the most common form of brain tumor, will recur once removed or to be certain that it will not develop into a malignant form. In a recent study published in the scientific journal Science Advances
American researchers have in fact taken a step forward to better define the prognosis of patients with this neoplasm.
About 4,500 new cases per year in Italy
Meningiomas are the most frequent neoplasm of the central nervous system and around 4,500 new cases are diagnosed in Italy every year. They are classified into three grades of increasing aggressiveness, but about 95% of them are benign grade I tumors. They usually have a very slow growth (1-2 millimeters per year) and, unlike malignant brain tumors, they do not have a tendency to invade brain tissue and replace it, but to compress it from the outside leaving the brain and its functions basically intact. Due to the slow growth, meningiomas can become symptomatic when already large in size without the patient noticing anything in the previous months or years. From a microscopic point of view, meningiomas have been divided according to biological aggression into 3 degrees: grade I (benign), grade II (atypical) and grade III (malignant) – he explains Enrico Franceschi, acting director of the Oncology of the nervous system, IRCCS Institute of Neurological Sciences of Bologna -. This classification is not sufficient to fully establish the prognosis of patients as the clinical behavior of these neoplasms can be variable, and in some cases even meningiomas defined as grade I and II can be more aggressive, therefore it is of fundamental importance to be able to identify them.
The study with different techniques
Precisely for this reason, the group of experts of the Baylor College of Medicine and of the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital analyzed 365 meningiomas of grades I and II, integrating the information obtained under the microscope with multiple genetic profiling strategies: in practice they used various advanced diagnostic techniques for genetic and epigenetic analysis (RNA sequencing, cytogenetic and DNA methylation profile). Their conclusions indicate that this is possible more accurately distinguish truly benign tumors from more aggressive ones. A decisive step to be able to establish the most correct course of treatment for the patient and to know, with greater certainty, when surgical removal alone is enough and when, on the other hand, further therapies are necessary to reduce the chances of a relapse. For other types of brain tumors, such as gliomas and medulloblastomas, the histological classification (the one made by analyzing the tumor cells under a microscope) has been replaced by the molecular one, more precise and useful in predicting the course of the disease – comments one of the main authors of study, Akash J. Patel, Baylor St. Luke’s Medical Center neurosurgeon -. We hope that this will also occur for meningiomas within a few years.
Know the subtype to choose the treatments
Meningiomas are more common in adults and the elderly. In many cases, when they are small, they are occasional findings, that is, they are discovered by chance in CT or MRI brain scans performed for other reasons. The main surgical treatment and in some circumstances radiation therapy is additionally used. This study has shown that, thanks to molecular biology, we can identify three different biological groups of meningioma – concludes Franceschi -: two with excellent prognosis and one particularly aggressive, with a high chromosomal instability, for which there is need to develop more effective therapies. These new classification approaches on the basis of genetic and epigenetic characteristics have the important implication of providing the patient, after surgery, with a better definition of the prognosis and therefore directing him to the most appropriate diagnostic-therapeutic pathways.
February 14, 2022 (change February 14, 2022 | 18:53)
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