2024-01-12 09:37:03
Par Lucie Fraisse
Published on 12 Jan 24 at 10:37 See my news Follow News Toulouse
It is a very technical discovery and brings hope for patients suffering from glioblastoma, the most common form of brain cancer in adults. A clinical trial carried out under the aegis of Professor Elisabeth Moyal, head of the radiotherapy department at the IUCT-Oncopole of Toulouse and head of the RADOPT team at the Toulouse Cancer Research Center (CRCT), made it possible to show that‘a new medical imaging technique might improve the prognosis of patients.
A very aggressive tumor
“Glioblastoma is an extremely aggressive tumor, explains Professor Elisabeth Moyal. It can affect everyone. Even if men are more affected and there is a peak at 60 years of age, we notice that there are more and more young patients. The incidence of the disease has doubled in thirty years, without knowing why. »
An illness in grim prognosiswhich is treated by surgery – when possible depending on the location of the tumor – followed by treatment by radiotherapy and chemotherapy.
“Surgery cannot completely remove the tumor, because it is very infiltrative »explains Professor Moyal.
Numerous relapses
Despite treatments, most patients face a relapse, especially in these infiltrated areas around the body of the tumor which might not be removed during surgery.
It is these peritumoral areas that Professor Moyal and his Inserm team analyzed more precisely. Via the “ magnetic resonance spectroscopy » a specific MRI technique capable of producing very high resolution imageswhich made it possible to study the metabolism of these tumors in detail.
Clinical trial with sixteen patients
“Several years ago, using this technique, we showed that hypermetabolic areas predicted where there would be relapses, even if this peritumoral area had been irradiated, explains Professor Elisabeth Moyal. We then wanted to see and study which cells were in these metabolic zones where relapse would occur. Our hypothesis: these areas were richer in tumor stem cells, that is to say in the roots of the tumor, cells known to be more aggressive and resistant to treatments. “
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A clinical trial was developed in partnership with the Toulouse University Hospital, including 16 patients with glioblastoma, with the assistance of Dr Lubrano, neurosurgeon. These sixteen patients benefited from a Conventional MRI and magnetic resonance spectroscopy before their operation (then in their follow-ups). Guided by these extremely precise images, a surgeon from the neurosurgery department of Toulouse University Hospital was able to carry out biopsies, including in difficult-to-access peritumoral areas.
More numerous and more aggressive cells
The samples were then sent to Professor Moyal’s INSERM team at the CRCT and analyzed by Dr Anthony Lemarié, lecturer at Paul-Sabatier University and Caroline Delmas, laboratory engineer at the Oncopole Claudius Regaud.
The analyzes confirmed the team’s working hypothesis: glioblastoma stem cells are much more numerous and more aggressive in the hypermetabolic zones of the regions surrounding the tumor. “Not only are they more numerous, but they express genes involved in aggressiveness and therapeutic resistance. This explains why the tumors return to these places,” explains Professor Moyal.
Improve the prognosis
The challenge is therefore to remove these metabolic zones enriched in tumor stem cells – when surgery is possible at this level – and to target them more finely with radiotherapy, in association with new drugs targeting the aggressive genes expressed by these stem cells, in order to improve the prognosis of patients.
The combination of the two imaging techniques MRI and magnetic resonance spectroscopy, before surgery, might allow surgeons to gain precision in resection and remove foci of regrowth, if they are not located in a functional area of the brain.
Professor Moyal
New clinical trials combining radiotherapy guided by this imaging with new drugs targeting these tumor stem cells might also be developed.
The results of this clinical trial conducted at IUCT-Oncopole were published in the journal Science Advance in November 2023.
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