Evaluación del papel de la PET/TC con [68Ga]Ga-PSMA I&T en la evaluación de la respuesta a la terapia con docetaxel en pacientes con cáncer de próstata resistente a la castración / Assessment of the role of Ga-68 PSMA I&T PET/CT in response evaluation to docetaxel therapy in castration resistant prostate cancer patients

OBJETIVO: Ha habido pocos estudios que investiguen el papel de los ligandos de PSMA en la evaluación de la respuesta al tratamiento de los casos de cáncer de próstata (CP) resistente a la castración metastatizado (CRPCm). En el presente estudio nos proponemos evaluar la capacidad del antígeno de membrana específico de la próstata (PSMA) 68Ga-tomografía por emisión de positrones/tomografía computarizada (PET/TC) en la evaluación de la respuesta terapéutica en pacientes bajo terapia de docetaxel para el CP. MATERIAL Y MÉTODOS: Se analizaron retrospectivamente las historias clínicas de todos los pacientes de CRPCm tratados con docetaxel y referidos a nuestro departamento para imagenología TEP/TC 68Ga-PSMA I&T. Se incluyó en el estudio 16 a pacientes (edad media 69 años, rango 52-82 años) con CP resistente a la castración que recibían tratamiento paliativo con docetaxel y que se habían sometido a una PET/TC 68Ga-PSMA. Se realizaron imágenes 68Ga-PSMA I&T PET/TC y se midieron los niveles de antígeno específico de próstata (PSA) al inicio del estudio antes de la administración del docetaxel (PET1) y después de al menos 3 ciclos (rango 4-12) de quimioterapia (PET2). Se realizó una comparación basada en el paciente y en la lesión de los hallazgos del PET2 con los hallazgos del PET1. RESULTADOS: Se encontró que el cambio (disminución) observado en los valores SUVmáx de los ganglios linfáticos y la glándula prostática/lecho prostático después del tratamiento en comparación con el pretratamiento fue estadísticamente significativo (p = 0,033). Tres de 16 pacientes (19%) se clasificaron como enfermedad progresiva (ED), 4/16 (25%) como enfermedad estable (EE), 9/16 (56%) como remisión parcial (RP) radiológicamente. Se observó una tendencia creciente del PSA (TC) en 4 pacientes (25%) y una tendencia decreciente del PSA (DT) en 3 pacientes (18%). Nueve pacientes mostraron una respuesta del PSA del 2% (56%). De los 4 pacientes que mostraron EE, 3 tenían IT, 3 tenían BR. De los 9 pacientes que mostraron RP en los estudios de TEP, 8 pacientes mostraron BR y un paciente mostró DT. CONCLUSIÓN: Las imágenes con 68Ga-PSMA PET/TC mostraron una gran concordancia con la evaluación de la BR en cuanto a los niveles de PSA, especialmente en los pacientes que mostraron una buena respuesta a la terapia. 68Ga-PSMA PET/TC también fue exitoso en la identificación de la enfermedad progresiva en pacientes que mostraron una paradójica disminución de los niveles de PSA

OBJECTIVE: There have been only few studies investigating the role of PSMA ligands in the therapy response assessment of metastasized castration resistant prostate cancer (mCRPC) cases. In this study we aimed at evaluating the capability of 68Ga- prostate-specific membrane antigen (PSMA) I&T positron emission tomography/computerized tomography (PET/CT) in the assessment of therapeutic response in patients under docetaxel therapy for prostate cancer (PCa). MATERIAL AND METHODS: The clinical records of all mCRPC patients treated with docetaxel and referred to our department for 68Ga-PSMA I&T PET/CT imaging were retrospectively analysed. Sixteen patients (mean age 69 years, range 52-82 years) with castration-resistant prostate cancer patients receiving palliative docetaxel therapy and had undergone 68Ga-PSMA I&T PET/CT scan were included in the study. 68Ga-PSMA I&T PET/CT imaging was done and prostate specific antigen (PSA) levels were measured at baseline before administration of docetaxel (PET1) and after at least 3 cycles (range 4-12) of chemotherapy (PET2). Patient-based as well as lesion-based comparison of PET2 findings with PET1 findings were done. RESULTS: The change (decrease) observed in lymph node and prostate gland/prostatic bed SUVmax values after treatment compared to pretreatment was found to be statistically significant (P=.033). 3/16 patients (19%) were classified as progressive disease (PD), 4/16 (25%) as stable disease (SD), 9/16 (56%) as partial remission (PR) radiologically. An increasing PSA trend (IT) was observed in 4 patients (25%) and a decreasing PSA trend (DT) in 3 patients (18%). Nine patients showed a PSA response of ≥ 50% (56%). Of the 4 patients showing SD, 3 had IT, 3 had BR. Of the 9 patients who showed PR on PET studies, 8 patients showed BR and 1 patient showed DT. CONCLUSION: Imaging with 68Ga-PSMA PET/CT showed great concordance with biochemical response evaluation in terms of PSA levels, especially in patients showing good response to therapy. 68Ga-PSMA PET/CT was also successful in identifying progressive disease in patients showing paradoxical decline in PSA levels

Assessment of the role of Ga-68 PSMA I&T PET/CT in response evaluation to docetaxel therapy in castration resistant prostate cancer patients. / Evaluación del papel de la PET/TC con [68Ga]Ga-PSMA I&T en la evaluación de la respuesta a la terapia con docetaxel en pacientes con cáncer de próstata resistente a la castración.

OBJECTIVE: There have been only few studies investigating the role of PSMA ligands in the therapy response assessment of metastasized castration resistant prostate cancer (mCRPC) cases. In this study we aimed at evaluating the capability of 68Ga- prostate-specific membrane antigen (PSMA) I&T positron emission tomography/computerized tomography (PET/CT) in the assessment of therapeutic response in patients under docetaxel therapy for prostate cancer (PCa). MATERIAL AND METHODS: The clinical records of all mCRPC patients treated with docetaxel and referred to our department for 68Ga-PSMA I&T PET/CT imaging were retrospectively analysed. Sixteen patients (mean age 69 years, range 52-82 years) with castration-resistant prostate cancer patients receiving palliative docetaxel therapy and had undergone 68Ga-PSMA I&T PET/CT scan were included in the study. 68Ga-PSMA I&T PET/CT imaging was done and prostate specific antigen (PSA) levels were measured at baseline before administration of docetaxel (PET1) and after at least 3 cycles (range 4-12) of chemotherapy (PET2). Patient-based as well as lesion-based comparison of PET2 findings with PET1 findings were done. RESULTS: The change (decrease) observed in lymph node and prostate gland/prostatic bed SUVmax values after treatment compared to pretreatment was found to be statistically significant (P=.033). 3/16 patients (19%) were classified as progressive disease (PD), 4/16 (25%) as stable disease (SD), 9/16 (56%) as partial remission (PR) radiologically. An increasing PSA trend (IT) was observed in 4 patients (25%) and a decreasing PSA trend (DT) in 3 patients (18%). Nine patients showed a PSA response of ≥ 50% (56%). Of the 4 patients showing SD, 3 had IT, 3 had BR. Of the 9 patients who showed PR on PET studies, 8 patients showed BR and 1 patient showed DT. CONCLUSION: Imaging with 68Ga-PSMA PET/CT showed great concordance with biochemical response evaluation in terms of PSA levels, especially in patients showing good response to therapy. 68Ga-PSMA PET/CT was also successful in identifying progressive disease in patients showing paradoxical decline in PSA levels.

Eficacia de la imagen precoz con 68Ga-PSMA-I&T para la discriminación de lesiones en los pacientes con cáncer de próstata / Efficacy of early imaging with 68Ga-PSMA-I&T in the discrimination of pelvic lesions in prostate cancer patients

Objetivo: El 68Ga-PSMA muestra captación en las lesiones malignas de los pacientes de cáncer de próstata a los 5 min postinyección. Los estudios realizados para comprender el valor de añadir una imagen pélvica precoz al protocolo de imagen de 68Ga-PSMA-11 PET/TC muestran resultados contradictorios. En este estudio, planificamos la evaluación de la relevancia de añadir una imagen precoz a 68Ga-PSMA-I&T PET/TC en los pacientes con cáncer de próstata. Materiales y métodos: Reunimos a un total de 35 pacientes con cáncer de próstata, a quienes se les prescribió 68Ga-PSMA-I&T PET/TC para reestadificar la enfermedad, debido a sospecha de recidiva tras la terapia definitiva. En primer lugar, se obtuvo una imagen pélvica estática precoz, a un máximo de 300 s tras la inyección del radiotrazador. A los 60 min de la inyección se realizó una PET/TC de cuerpo entero, con un tiempo de emisión de 3min por posición del lecho. Se compararon las lesiones categorizadas en las imágenes precoces como recidiva local, lesión ósea y metástasis ganglionar con las imágenes tardías en términos de lesiones detectadas y valores SUVmax. Resultados: La68Ga-PSMA-I&T PET/TC fue positiva en 23 de los 35 pacientes (65,7%). Se observó una captación patológica en el lecho prostático, en los ganglios pélvicos y en los huesos en 17 pacientes (48,5%), 12 pacientes (34,2%) y 13 pacientes (37,1%), respectivamente. En un paciente, se detectó una captación incrementada patológica focal en el lecho prostático con un valor SUVmax de 5,8, aunque esta lesión desapareció en las imágenes tardías. Los valores SUVmax medios de las lesiones en el lecho prostático fueron 13,7±12,1 frente a 26,3±23,8 en los estudios a los 5min y 60min, respectivamente (p<0,001). En un paciente, la captación patológica ganglionar en el estudio temprano desapareció en el estudio tardío, mientras que en otro paciente la acumulación de actividad se detectó en un ganglio pélvico en el estudio tardío, pero no se detectó ningún ganglio en el estudio temprano. Los valores SUVmax ganglionares medios fueron 12,1±8,8 frente a 26,3±22,6 en los estudios a los 5min y 60min, respectivamente (p<0,001). Los valores SUVmax medios de las lesiones óseas fueron 11,4±6,9 frente a 15±10,7 en los estudios a los 5min y 60min, respectivamente. Conclusión: Nuestro estudio es el primero en la literatura que evalúa el impacto de añadir una imagen pélvica estática temprana a 68Ga-PSMA-I&T, para valorar la tasa de detección de las lesiones. Aunque no se produjo una discordancia marcada entre los 2conjuntos de imágenes, la adición de una imagen temprana al protocolo de imagen de 68Ga-PSMA-I&T podría incrementar la eficacia en la detección de las lesiones pélvicas malignas, lo cual podría reflejar un rápido aclaramiento, con el riesgo de que fuera enmascarado por la actividad del sistema urinario

Objective: 68Ga-PSMA-uptake shows accumulation in the malignant lesions of prostate cancer patients as early as 5min p.i. Studies indicate the value of adding an early image of the pelvis to the imaging protocol of 68Ga-PSMA-11 PET/CT scan showed contradictory results. In this study we planned to assess the significance of an additional early imaging in 68Ga-PSMA-I&T PET/CT imaging in prostate cancer patients. Materials and methods: A total of 35 prostate cancer patients referred to 68Ga-PSMA-I&T PET/CT imaging for restaging of the disease due to suspicion of relapse after definitive therapy were enrolled. First an early static pelvic image was obtained at a maximum of 300s following injection of the radiotracer. Sixty minutes postinjection a whole-body PET/CT scan was conducted with an emission time of 3min per bed position. The lesions which were categorized as local recurrence, bone lesion and lymph node metástasis in the early images, were compared with the late images in terms of number of lesions detected and SUVmax values. Results: 68Ga-PSMA-I&T PET/CT was positive in 23 of 35 patients (65.7%). A pathological uptake was observed in the prostatic bed site, in the pelvic lymph nodes, and in the bones in 17 patients (48.5%), 12 patients (34.2%), and 13 patients (37.1%), respectively. In one patient, focal pathological increased uptake in the prostatic bed with a SUVmax value of 5.8 was detected but this lesion disappeared in the late images. The average SUVmax values of the lesions in the prostatic bed were 13.7±12.1 versus 26.3±23.8 in the 5min and 60min studies respectively (p<0.001). In one patient, the pathological uptake in the lymph node in the early study cleared in the late study, whereas in another accumulation of activity was detected in a pelvic lymph node in the late study, while there was no lymph node detected in the early study. The average SUVmax values of the lymph nodes were 12.1±8.8 versus 26.3±22.6 in the 5min and 60min studies respectively (p<0.001). The average SUVmax values of the bone lesions were 11.4±6.9 versus 15±10.7 in the 5min and 60min studies respectively. Conclusion: Our study is the first in the literature to evaluate the impact of adding an early static pelvic image to the 68Ga-PSMA-I&T scan, in the detection rate of the lesions. Although there was no marked discordance between the 2sets of images, the addition of an early image to the imaging protocol of 68Ga-PSMA-I&T scan would increase the efficacy of detection of malignant lesions in the pelvis, which might show rapid clearance and has the risk of being masked by the urinary system activity

Efficacy of early imaging with 68Ga-PSMA-I&T in the discrimination of pelvic lesions in prostate cancer patients. / Eficacia de la imagen precoz con 68Ga-PSMA-I&T para la discriminación de lesiones en los pacientes con cáncer de próstata.

OBJECTIVE: 68Ga-PSMA-uptake shows accumulation in the malignant lesions of prostate cancer patients as early as 5min p.i. Studies indicate the value of adding an early image of the pelvis to the imaging protocol of 68Ga-PSMA-11 PET/CT scan showed contradictory results. In this study we planned to assess the significance of an additional early imaging in 68Ga-PSMA-I&T PET/CT imaging in prostate cancer patients. MATERIALS AND METHODS: A total of 35 prostate cancer patients referred to 68Ga-PSMA-I&T PET/CT imaging for restaging of the disease due to suspicion of relapse after definitive therapy were enrolled. First an early static pelvic image was obtained at a maximum of 300s following injection of the radiotracer. Sixty minutes postinjection a whole-body PET/CT scan was conducted with an emission time of 3min per bed position. The lesions which were categorized as local recurrence, bone lesion and lymph node metástasis in the early images, were compared with the late images in terms of number of lesions detected and SUVmax values. RESULTS: 68Ga-PSMA-I&T PET/CT was positive in 23 of 35 patients (65.7%). A pathological uptake was observed in the prostatic bed site, in the pelvic lymph nodes, and in the bones in 17 patients (48.5%), 12 patients (34.2%), and 13 patients (37.1%), respectively. In one patient, focal pathological increased uptake in the prostatic bed with a SUVmax value of 5.8 was detected but this lesion disappeared in the late images. The average SUVmax values of the lesions in the prostatic bed were 13.7±12.1 versus 26.3±23.8 in the 5min and 60min studies respectively (p<0.001). In one patient, the pathological uptake in the lymph node in the early study cleared in the late study, whereas in another accumulation of activity was detected in a pelvic lymph node in the late study, while there was no lymph node detected in the early study. The average SUVmax values of the lymph nodes were 12.1±8.8 versus 26.3±22.6 in the 5min and 60min studies respectively (p<0.001). The average SUVmax values of the bone lesions were 11.4±6.9 versus 15±10.7 in the 5min and 60min studies respectively. CONCLUSION: Our study is the first in the literature to evaluate the impact of adding an early static pelvic image to the 68Ga-PSMA-I&T scan, in the detection rate of the lesions. Although there was no marked discordance between the 2sets of images, the addition of an early image to the imaging protocol of 68Ga-PSMA-I&T scan would increase the efficacy of detection of malignant lesions in the pelvis, which might show rapid clearance and has the risk of being masked by the urinary system activity.

Incidental thyroid lesions on FDG-PET/CT: a prevalence study and proposition of management.

AIM: Thyroid incidentaloma is defined as an unsuspected, asymptomatic thyroid lesion that is discovered on an imaging study. The purpose of this study is to determine incidentally identified thyroid lesions by FDG-PET/CT in cancer patients by virtue of preoperative staging and to pay attention how should be the management of these patients with thyroid lesion. METHODS: From January 2011 to January 2013, 2654 patients underwent FDG-PET/CT in our institution. Among them, 34 patients had thyroid incidentaloma. All patients underwent ultrasonographic (US) examination. If there is a nodul, fine needle aspirations (FNA) were performed to these patients. We did not perform FNA to patients who had diffuse thyroid uptake. Patients were divided into two groups; malign and non-malign patients according to FNA histo-pathologic results. Group 1 (N.=11) diagnosed malignancy in histo-pathologic evaluation, group 2 (N.=23) could not diagnosed malignancy in histo-pathologic, clinic and radiologic evaluation. These two groups were compared statistically in terms of SUV max levels that reached in PET examinations. RESULTS: Incidentally thyroid lesions were found in 34 patients in the course of FDG-PET/CT examination (25 females and 9 males), mean age 57.7 years. Nodular goitre in 12 patients, hyperthyroidism in 2 patients, sub-clinic hyperthyroidism in 3 patients and hashimoto thyroiditis in 6 patients were diagnosed in non-malignancy group (Group-2). Group 1 included 11 patients with incidentally diagnosed thyroid malignancy. 11 patients malignancy diagnoses were verified by FNA and 9 of them were operated. In PET evaluation thyroid up-take was diffuse in 9 patients, at left lob in 12 patients and at right lop in 13 patients. When we compared the groups according to SUV max levels; we found that malignant thyroid lesions had a significantly higher (P<0.001) SUVmax than benign thyroid lesions. A cut off SUVmax value (>6.2) was found in the study. CONCLUSION: The incidental finding of focal thyroid uptake on FDG-PET scanning has an elevated malignancy risk from other thyroid nodules. According to our knowledge diagnose, treatment and follow-up of these patients should be in multidiscipliner approach. Oncology, endocrinology, endocrine surgeon, interventional radiology, pathology and psychiatry should be gathered in multidiscipliner team. For these reason these patients need more careful evaluation.