RESUMEN

We describe two patients with a confirmed diagnosis of high-grade gliomas (grades III/IV), both presenting with O6-methylguanine-DNA methyltransferase (MGMT) methylated and isocitrate dehydrogenase (IDH-1) mutated who, after subtotal resection, were submitted to chemoradiation and followed by PCV, a multiple drug regimen (procarbazine, lomustine, and vincristine) associated with cannabidiol (CBD). Both patients presented with satisfactory clinical and imaging responses at periodic evaluations. Immediately after chemoradiation therapy, one of the patients presented with an exacerbated and precocious pseudoprogression (PSD) assessed by magnetic resonance imaging (MRI), which was resolved in a short period. The other patient presented with a marked remission of altered areas compared with the post-operative scans as assessed by MRI. Such aspects are not commonly observed in patients only treated with conventional modalities. This observation might highlight the potential effect of CBD to increase PSD or improve chemoradiation responses that impact survival. Further investigation with more patients and critical molecular analyses should be performed.

RESUMEN

The assessment of response to therapy in glioblastoma remains a challenge, because the surrogate measures of survival are subject to radiographic misinterpretation. A solid and reliable definition of progression is needed for both clinical decision-making and for evaluating response within the clinical trials. Historically, assessment criteria have used radiologic and clinical features aimed to correctly classify patients into progressive or non-progressive disease. The widely used RANO criteria are a valuable tool in disease evaluation, both in the clinical setting and in the clinical trials. However, assessment criteria have certain limitations that emerging image techniques have tried to overcome. Differentiating true progression from treatment-related changes (like pseudoprogression or pseudoresponse) is crucial in order not to prematurely discontinue adjuvant chemotherapy or redirect the patient to second-line options. This fact underscores the need for advanced radiologic techniques, like specific diffusion and perfusion MRI sequences, MR spectroscopy and PET, which seem to play a role in distinguishing these phenomena.

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RESUMEN

Positron emission tomography (PET) with 11C-methionine (11C-methionine PET/CT) is a new technique used to evaluate primary central nervous system (CNS) tumors. We describe our experience regarding the first 4 patients with glial tumors and 11C-methionine PET/CT. This is a descriptive, observational and prospective study of 4 patients between 38-50 years of age, with different gliomas (WHO classification). MRI and 11C-methionine PET/CT were performed in all cases. Case 1, gliomatosis cerebri grade II post-radiotherapy. Case 2, oligodendroglioma grade II diagnosed and treated with radiotherapy in 1993. Case 3, glioblastoma grade IV post-radiotherapy + temozolomide. Case 4, anaplastic oligoastrocytoma grade III post-radiotherapy + temozolomide. The pattern of 11C-methionine uptake compared with MRI showed tumor progression in cases 1, 3 and 4, and in case 2 showed uptake although the final diagnosis was pseudoprogression. Unlike 18fluordeoxiglucose PET/TC, 11C-methionine uptake in normal brain tissue and pseudoprogression is low, and gliomas are displayed as metabolically active areas. The 11C-methionine PET/CT provided valuable information on the tumoral behavior and extension, although in one case presented did not differentiate tumor progression from pseudoprogression. 11C-methionine PET/CT could be a useful tool in the study and follow-up to patients with gliomas.

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RESUMEN

La tomografía por emisión de positrones con metionina carbono 11 (11C-metionina PET/TC) se utiliza en la evaluación de los tumores primarios del sistema nervioso central. Describimos nuestra experiencia sobre los primeros 4 pacientes con tumores de la serie glial estudiados con 11C-metionina PET/TC. Este es un estudio descriptivo, observacional y prospectivo. Se presentan 4 pacientes entre 38-50 años de edad con diagnóstico de gliomas (clasificación de la OMS). A todos se les realizó RM y 11C-metionina PET/TC para evaluar actividad tumoral y diferenciar progresión tumoral de pseudoprogresión. Caso 1, gliomatosis cerebri grado II posradioterapia. Caso 2, glioblastoma grado IV postratamiento RT + temozolomida. Caso 3, oligodendroglioma grado II posradioterapia en 1993. Caso 4, oligoastrocitoma anaplásico grado III postratamiento RT + temozolomida. El patrón de captación de la 11C-metionina comparativamente con la RM, demostró progresión tumoral en los casos 1, 3 y 4; en el caso 2 mostró captación aunque el diagnóstico final fue pseudoprogresión. A diferencia del PET con 18fluordeoxiglucosa, la captación de 11C-metionina en el tejido cerebral normal y en la pseudoprogresión es baja, y los gliomas se visualizan como áreas metabólicamente activas. En los casos presentados, el 11C-metionina PET/TC proveyó información valiosa sobre el comportamiento y extensión de la lesión, aunque en uno de los casos presentados no diferenció progresión tumoral de pseudoprogresión. El 11C-metionina PET/TC sería una herramienta útil en el estudio y seguimiento de los pacientes con gliomas.(AU)

Positron emission tomography (PET) with 11C-methionine (11C-methionine PET/CT) is a new technique used to evaluate primary central nervous system (CNS) tumors. We describe our experience regarding the first 4 patients with glial tumors and 11C-methionine PET/CT. This is a descriptive, observational and prospective study of 4 patients between 38-50 years of age, with different gliomas (WHO classification). MRI and 11C-methionine PET/CT were performed in all cases. Case 1, gliomatosis cerebri grade II post-radiotherapy. Case 2, oligodendroglioma grade II diagnosed and treated with radiotherapy in 1993. Case 3, glioblastoma grade IV post-radiotherapy + temozolomide. Case 4, anaplastic oligoastrocytoma grade III post-radiotherapy + temozolomide. The pattern of 11C-methionine uptake compared with MRI showed tumor progression in cases 1, 3 and 4, and in case 2 showed uptake although the final diagnosis was pseudoprogression. Unlike 18fluordeoxiglucose PET/TC, 11C-methionine uptake in normal brain tissue and pseudoprogression is low, and gliomas are displayed as metabolically active areas. The 11C-methionine PET/CT provided valuable information on the tumoral behavior and extension, although in one case presented did not differentiate tumor progression from pseudoprogression. 11C-methionine PET/CT could be a useful tool in the study and follow-up to patients with gliomas.(AU)

Asunto(s)

RESUMEN

La tomografía por emisión de positrones con metionina carbono 11 (11C-metionina PET/TC) se utiliza en la evaluación de los tumores primarios del sistema nervioso central. Describimos nuestra experiencia sobre los primeros 4 pacientes con tumores de la serie glial estudiados con 11C-metionina PET/TC. Este es un estudio descriptivo, observacional y prospectivo. Se presentan 4 pacientes entre 38-50 años de edad con diagnóstico de gliomas (clasificación de la OMS). A todos se les realizó RM y 11C-metionina PET/TC para evaluar actividad tumoral y diferenciar progresión tumoral de pseudoprogresión. Caso 1, gliomatosis cerebri grado II posradioterapia. Caso 2, glioblastoma grado IV postratamiento RT + temozolomida. Caso 3, oligodendroglioma grado II posradioterapia en 1993. Caso 4, oligoastrocitoma anaplásico grado III postratamiento RT + temozolomida. El patrón de captación de la 11C-metionina comparativamente con la RM, demostró progresión tumoral en los casos 1, 3 y 4; en el caso 2 mostró captación aunque el diagnóstico final fue pseudoprogresión. A diferencia del PET con 18fluordeoxiglucosa, la captación de 11C-metionina en el tejido cerebral normal y en la pseudoprogresión es baja, y los gliomas se visualizan como áreas metabólicamente activas. En los casos presentados, el 11C-metionina PET/TC proveyó información valiosa sobre el comportamiento y extensión de la lesión, aunque en uno de los casos presentados no diferenció progresión tumoral de pseudoprogresión. El 11C-metionina PET/TC sería una herramienta útil en el estudio y seguimiento de los pacientes con gliomas.

Positron emission tomography (PET) with 11C-methionine (11C-methionine PET/CT) is a new technique used to evaluate primary central nervous system (CNS) tumors. We describe our experience regarding the first 4 patients with glial tumors and 11C-methionine PET/CT. This is a descriptive, observational and prospective study of 4 patients between 38-50 years of age, with different gliomas (WHO classification). MRI and 11C-methionine PET/CT were performed in all cases. Case 1, gliomatosis cerebri grade II post-radiotherapy. Case 2, oligodendroglioma grade II diagnosed and treated with radiotherapy in 1993. Case 3, glioblastoma grade IV post-radiotherapy + temozolomide. Case 4, anaplastic oligoastrocytoma grade III post-radiotherapy + temozolomide. The pattern of 11C-methionine uptake compared with MRI showed tumor progression in cases 1, 3 and 4, and in case 2 showed uptake although the final diagnosis was pseudoprogression. Unlike 18fluordeoxiglucose PET/TC, 11C-methionine uptake in normal brain tissue and pseudoprogression is low, and gliomas are displayed as metabolically active areas. The 11C-methionine PET/CT provided valuable information on the tumoral behavior and extension, although in one case presented did not differentiate tumor progression from pseudoprogression. 11C-methionine PET/CT could be a useful tool in the study and follow-up to patients with gliomas.

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