PET/TC con FAPI: procedimiento y revisión de la evidencia en oncología / PET/CT FAPI: Procedure and evidence review in oncology

Las neoplasias se componen de células malignas tumorales que se encuentran rodeadas de diversos elementos celulares no tumorales, que conforman el microambiente o estroma tumoral. La evidencia sobre la importancia este último no ha parado de crecer en los últimos años ya que desempeña un papel necesario para la proliferación celular, la invasión tisular, la angiogénesis y la migración celular. El paradigma es la familia de los nuevos radiofármacos inhibidores de la proteína de activación de fibroblastos (FAPI) que nos muestran la densidad de dicha proteína (FAP) que se encuentra sobreexpresada en la membrana celular de los fibroblastos activados asociados al cáncer (CAF), y su presencia está relacionada con un mal pronóstico. En este documento de formación continuada se incluye el procedimiento para la realización de la tomografía por emisión de positrones/tomografía computarizada (PET/TC) con FAPI, la biodistribución y las potenciales aplicaciones clínicas en oncología publicadas hasta el momento. (AU)

Neoplasms are composed of malignant tumour cells, which are surrounded by other non-tumour cellular elements, what has been defined as the microenvironment or tumour stroma. Evidence on the importance of the tumour microenvironment has not stopped growing in recent years. It plays a central role for cell proliferation, tissue invasion, angiogenesis and cell migration. The paradigm is the family of new FAPI radiopharmaceuticals that show us the density of the fibroblast activation protein (FAP) that is overexpressed in the cell membrane of activated cancer-associated fibroblasts (CAF), and its presence is related to poor prognosis. The paradigm is the family of new FAPI radiopharmaceuticals, which represents the density of activated fibroblasts associated with cancer. This educational document includes the procedure for performing PET/CT FAPI, biodistribution and the main potentially clinical applications in oncology to date. (AU)

Aplicación clínica de la [18F]FDG PET/TC en el linfoma folicular / Clinical application of [18F]FDG PET/CT in follicular lymphoma

El objetivo de este trabajo fue revisar el papel de la [18F]FDG PET/TC en el linfoma folicular (LF). Tras confirmarse que a pesar de su carácter indolente este tipo de linfoma habitualmente muestra avidez por el radiotrazador, la [18F]FDG PET/TC fue cobrando una importancia progresivamente mayor hasta ser considerada como la técnica de elección para su estadificación, re-estadificación y valoración de respuesta al tratamiento. Múltiples estudios han demostrado el impacto que supone en el manejo de estos pacientes (puede cambiar el estadio de la enfermedad en una proporción significativa de casos y condicionar modificaciones en el tratamiento), su superioridad respecto a la TC (principalmente por la capacidad para distinguir tejido tumoral viable de tejido fibrótico residual) y su valor pronóstico. Esto último se atribuyó inicialmente de forma exclusiva al grado de respuesta metabólica alcanzado tras el tratamiento, que ha probado ser un factor predictivo fuerte e independiente de supervivencia libre de progresión (SLP) y supervivencia global (SG), de modo que una [18F]FDG PET/TC negativa podría considerarse una garantía para los pacientes con LF con elevada carga tumoral. No obstante, la obtención de parámetros metabólicos semicuantitativos como el volumen metabólico tumoral o la glucólisis total de la lesión podría también aportar información a este respecto y ayudarnos potencialmente a identificar a los pacientes de mal pronóstico antes del inicio del tratamiento, de forma que se pueda adecuar el manejo y seguimiento al riesgo del paciente (AU)

The objective of the present paper was to review the clinical application of [18F]FDG PET/CT in follicular lymphoma (FL). Once it was clear that, despite it's characterized as indolent, this type of lymphoma usually shows a high [18F]FDG avidity, PET/CT became more important and it's now considered the standard technique in staging, re-staging and response evaluation. Many studies have shown its impact on the management of patients (as it can change the stage in a significant proportion of cases and lead to treatment modifications), its superiority over CT (mainly because it's able to distinguish fibrosis in residual masses from viable tumor) and its prognostic value. The latter was initially associated only to the degree of metabolic response, which has proved to be a strong and independent predictive factor in terms of disease-free survival (DFS) and overall survival (OS). Thus, a negative PET/CT scan could be considered a guarantee in high-tumor-burden follicular lymphoma patients. However, semiquantitative parameters such as metabolic tumor volume or total lesion glycolysis, may also provide useful information and help us to identify patients with poor prognosis, guiding a risk-adjusted management and follow-up (AU)

Clinical application of [18F]FDG PET/CT in follicular lymphoma.

The objective of the present paper was to review the clinical application of [18F]FDG PET/CT in follicular lymphoma (FL). Once it was clear that, despite it is characterized as indolent, this type of lymphoma usually shows a high [18F]FDG avidity, PET/CT became more important and it's now considered the standard technique in staging, re-staging and response evaluation. Many studies have shown its impact on the management of patients (as it can change the stage in a significant proportion of cases and lead to treatment modifications), its superiority over CT (mainly because it's able to distinguish fibrosis in residual masses from viable tumor) and its prognostic value. The latter was initially associated only to the degree of metabolic response, which has proved to be a strong and independent predictive factor in terms of disease-free survival (DFS) and overall survival (OS). Thus, a negative PET/CT scan could be considered a guarantee in high-tumor-burden follicular lymphoma patients. However, semiquantitative parameters such as metabolic tumor volume or total lesion glycolysis, may also provide useful information and help us to identify patients with poor prognosis, guiding a risk-adjusted management and follow-up.

Utilidad de los radioligandos PSMA en el diagnóstico y tratamiento del carcinoma de próstata / The role of PSMA radioligands in the diagnosis and treatment of prostate carcinoma

El cáncer de próstata (CP) es el tumor más frecuente en varones en Occidente y la quinta causa de muerte relacionada con el cáncer. El uso de radioligandos antígeno prostático específico de membrana (PSMA) ha supuesto un importante avance tanto en su diagnóstico, a través de la imagen molecular de tomografía por emisión de positrones (PET), como en su tratamiento en fases avanzadas de la enfermedad. En este artículo, se hace una revisión de la aportación de los estudios PET con radioligandos PSMA en la estadificación inicial, en la detección tumoral en la recidiva bioquímica (elevación del antígeno prostático específico [PSA]) tras un tratamiento con intención curativa, y en los estadios más avanzados de la enfermedad (CP resistente a la castración o CPRC). Se analiza, además, la aportación de la terapia con radioligandos PSMA (PSMA-TRL) en pacientes con CPRC que progresan a la terapia estándar (AU)

Prostate cancer (PC) is the most common tumor in men in the West and the fifth leading cause of cancer-related death. The use of prostate-specific membrane antigen (PSMA) radioligands has represented an important advance in both in the diagnosis by positron emission tomography (PET) molecular imaging and the treatment of advanced stages of the disease. This article reviews the contribution of PET studies with PSMA radioligands in the initial staging, tumor detection in biochemical recurrence (elevation of PSA) after treatment with curative intent, and in the more advanced stages of the disease (castration-resistant PC [CRPC]). The contribution of PSMA radioligand therapy in CRPC patients who progress to standard therapy is also analyzed (AU)

The role of PSMA radioligands in the diagnosis and treatment of prostate carcinoma.

Prostate cancer (PC) is the most common tumor in men in the West and the fifth leading cause of cancer-related death. The use of PSMA radioligands has represented an important advance both in its diagnosis, through PET molecular imaging, and in its treatment in advanced stages of the disease. This article reviews the contribution of PET studies with PSMA radioligands in initial staging, in tumor detection in biochemical recurrence (elevation of PSA) after treatment with curative intent, and in the more advanced stages of the disease (castration resistant PC or CRPC). The contribution of PSMA radioligand therapy (PSMA-RLT) in CRPC patients who progress to standard therapy is also analyzed.

FDG PET/CT in colorectal cancer. / FDG PET/TC en el cáncer colorrectal.

Colorectal cancer is the third most frequent cancer worldwide. Although its incidence is increasing, mainly in those aged under50, mortality has decreased by 50% in the more developed countries, principally due to the adoption of new practices in prevention, diagnosis and treatment. In particular, the various diagnostic imaging modalities allow improved therapeutic decision-making, evaluation of the response and early detection of recurrence. The aim of this paper is to review the available scientific evidence on the value of positron emission tomography with 18F-FDG (18F-FDG PET/CT) in the colorectal cancer, with special emphasis on the indications of the guidelines and recommendations of the main international scientific associations regarding this imaging technique.

Comparative study of 18F-FDG PET/CT and CT angiography in detection of large vessel vasculitis. / Estudio comparativo de la PET/TC con 18F-FDG y la angiografía por TC en la detección de la vasculitis de grandes vasos.

OBJECTIVE: Compare 18F-FDG PET/CT and CTangio in the diagnosis of extracraneal large vessel involvement in patients with suspicion of large vessel vasculitis (LVV). MATERIAL AND METHODS: A retrospective database reviewed 59 patients with clinical suspicion of LVV undergoing 18F-FDG PET/CT and CTangio. In 55 patients PET/TC and CTangio were done simultaneously in the same machine and in 4 patients with a scan interval of<1 month. PET/CT analyses included qualitatively and quantitative analysis (ratio SUVmax 18F-FDG vessel/SUVmax liver). CTangio was assessed for concentric mural thickening, contrast wall enhancement and structural vascular changes as potential complications of vasculitis. RESULTS: 18F-FDG PET/CT and CTangio show high specificity (97.2%) for LVV diagnosis, with an excellent sensitivity for 18F-FDG PET/CT (95.6%) and lower for CTangio (60.9%), which leads to a high negative predictive value for 18F-FDG PET/CT (97.2%) and a high false negative rate for CTangio (39.1%). A 70% concordance between 18F-FDG PET/CT and CTangio was obtained (Kappa index 0.70± 0.095 (P<.001). CONCLUSION: The results show the greater potential of 18F-FDG PET/CT for the detection and extension of LVV. Therefore, 18F-FDG PET/CT should be exploited to the maximum and consider as the first line imaging technique in the extracranial diagnosis of LVV and its possible association with polymyalgia rheumatica. The addition of CTangio could be more indicated in patients with Takayasu arteritis and in long-standing and/or severe vasculitis since it increases the accuracy in the detection of possible vascular complications.

18F-FDG PET/CT in locally advanced cervical cancer: A review. / PET/TC con 18F-FDG en cáncer de cérvix localmente avanzado.

Cervical cancer is the second most common gynecological cancer worldwide. In locally advanced cervical cancer, 18F-FDG PET/CT has become important in the initial staging, particularly in the detection of nodal and distant metastasis, aspects with treatment implications and prognostic value. The aims of this study were to review the role of 18F-FDG PET/CT in uterine cervical cancer, according to the guidelines of the main scientific institutions (FIGO, NCCN, SEGO, SEOM, ESGO, and ESMO) and its diagnostic accuracy compared to conventional radiological techniques, as well as to review the acquisition protocol and its utility in radiotherapy planning, response assessment and detection of recurrence.

Radium-223 in the treatment of bone metastasis in patients with castration-resistant prostate cancer. Review and procedure. / Radio-223 en el tratamiento de metástasis óseas en pacientes con cáncer de próstata resistente a la castración. Revisión de la literatura y procedimiento.

Bone metastatic disease is the main cause of morbidity / mortality in patients with prostate cancer, presenting frequently as bone pain, pathological fractures or spinal cord compression, which requires early and timely therapy. Although, for the moment, the therapeutic window for its use has not been definitively established, radium-223 (223Ra), an alpha particle emitter, has proved to be an effective therapeutic tool, pre or post-chemotherapy, in patients with castration-resistant prostate cancer with symptomatic bone metastases and absence of visceral metastases, significantly modifying the prognosis of the disease. It is therefore imperative to define the ideal scenarios and the correct protocol for the use of this therapy and thus offer the greatest possible clinical benefit to the patient.

68Ga-PSMA PET/CT in prostate cancer. / La PET/TC con 68Ga-PSMA en el cáncer de próstata.

Positron emission tomography/computed tomography (PET/CT) with 68Ga-PSMA is a non-invasive diagnostic technique to image prostate cancer with increased prostate-specific membrane antigen (PSMA) expression. PSMA is a transmembrane protein present in all prostatic tissues. Increased PSMA expression is seen in several malignancies, although prostate cancer is the tumour where it presents higher concentrations. Almost all prostate adenocarcinomas show PSMA expression in most of lesions, primary and metastatic. Immunohistochemistry has demonstrated that the expression of PSMA increases in patients with de-differentiated, metastatic or hormone-refractory tumours. Moreover, the expression level of PSMA has a prognostic value for disease outcome. PET measures the three-dimensional distribution of 68Ga-PSMA, producing semi-quantitative images that allow for non-invasive assessment of PSMA expression.

Utilidad de la PET-TC en la valoración de la respuesta precoz al tratamiento en el linfoma B difuso de celula grande. Resultados preliminares / Utility of the PET-CT in the evaluation of early response to treatment in the diffuse large B-cell lymphoma. Preliminary results

Objetivo. Valorar la utilidad de la PET-TC con FDG tras los primeros ciclos de quimioterapia en la predicción de la respuesta al tratamiento en pacientes con linfoma B difuso de célula grande. Metodologia. Se incluyeron 20 pacientes (edad media: 48), 16 en la estadificación inicial y 4 por recidiva. La PET-TC se realizó en tres tiempos: 1) Basal, 2) Tras el primer-tercer ciclo (valoración de respuesta precoz), y 3) Al finalizar el tratamiento (valoración de respuesta final). Los hallazgos de la valoración precoz fueron correlacionados con la valoración final y el seguimiento. La valoración de la respuesta se estableció según la disminución de la captación de las lesiones (SUVmax). En la valoración precoz el indicador de buena respuesta (IBR) fue la reducción del SUVmax > 50% o la desaparición. Al final del tratamiento se determinó la respuesta metabólica completa (RMC) en ausencia de focos. El seguimiento fue superior a los 19 meses, estableciendo progresión/recidiva o sin evidencia de enfermedad (SEE). Resultados. La valoración precoz fue IBR en 16/16 pacientes de estadificación inicial (100%) y en 2/4 de recidiva (50%). Al final del tratamiento, en el primer grupo 14/16 pacientes con IBR consiguieron RMC y 1/16 RMP; 14 continuaron SEE y uno recidivó. En el segundo grupo 2/2 pacientes con IBR consiguieron RMC; uno continuó SEE y otro recidivó. Conclusion. La PET-TC tras los primeros ciclos de quimioterapia es útil para monitorizar el tratamiento debido a su elevado valor predictivo negativo (87,5%), modificando la terapia precozmente en los no respondedores(AU)

Objective. To assess the role of FDG-PET/CT performed after the first cycles of chemotherapy in the prediction of response to treatment in patients with diffuse large B-cell lymphoma. Methods. Twenty patients (mean age: 48 years) were included, 16 initial staging and 4 relapse. All patients underwent PET/CT at 3 times: 1) Baseline, 2) After 1-3 cycles of chemotherapy (early response assessment), and 3) End of treatment (evaluation of final response). Early PET/CT findings were correlated to the end-treatment PET/CT and follow-up. The evaluation of the response was established according to the decrease in uptake of the lesions (SUVmax). In the early assessment, a good response indicator (GRI) was obtained when the lesion disappeared or had more than 50% reduction in SUVmax. At the end of the treatment, a complete metabolic response (CMR) was determined in negative PET scans. Follow-up was superior to 19 months and final outcome was established as progression/relapse or no evidence of disease (NED). Results. At the early treatment evaluation, 16/16 patients of initial staging (100%) and 2/4 of relapse (50%) achieved GRI. At the end of treatment evaluation, 14/16 patients of initial staging with GRI achieved CMR and 1/16 PMR: 14 were alive with NED in the follow-up while 1 relapsed. In the second group, 2/2 patients with GRI achieved CMR (100%): 1 continued with NED in the follow-up and another relapsed. Conclusion. FDG-PET/CT after the first cycles of chemotherapy is useful to monitor treatment due to its high negative predictive value (87.5%), using it to modify treatment early in the non-responders(AU)

Utility of the PET-CT in the evaluation of early response to treatment in the diffuse large B-cell lymphoma. Preliminary results.

OBJECTIVE: To assess the role of FDG-PET/CT performed after the first cycles of chemotherapy in the prediction of response to treatment in patients with diffuse large B-cell lymphoma. METHODS: Twenty patients (mean age: 48 years) were included, 16 initial staging and 4 relapse. All patients underwent PET/CT at 3 times: 1) Baseline, 2) After 1-3 cycles of chemotherapy (early response assessment), and 3) End of treatment (evaluation of final response). Early PET/CT findings were correlated to the end-treatment PET/CT and follow-up. The evaluation of the response was established according to the decrease in uptake of the lesions (SUVmax). In the early assessment, a good response indicator (GRI) was obtained when the lesion disappeared or had more than 50% reduction in SUVmax. At the end of the treatment, a complete metabolic response (CMR) was determined in negative PET scans. Follow-up was superior to 19 months and final outcome was established as progression/relapse or no evidence of disease (NED). RESULTS: At the early treatment evaluation, 16/16 patients of initial staging (100%) and 2/4 of relapse (50%) achieved GRI. At the end of treatment evaluation, 14/16 patients of initial staging with GRI achieved CMR and 1/16 PMR: 14 were alive with NED in the follow-up while 1 relapsed. In the second group, 2/2 patients with GRI achieved CMR (100%): 1 continued with NED in the follow-up and another relapsed. CONCLUSION: FDG-PET/CT after the first cycles of chemotherapy is useful to monitor treatment due to its high negative predictive value (87.5%), using it to modify treatment early in the non-responders.