RESUMEN
PURPOSE: To compare the agreement between whole-body (WB) magnetic resonance (MR) imaging, 18F-FDG PET/CT, and skeletal survey (SS) in patients with multiple myeloma (MM) for diagnosis, initial staging, response evaluation, and early detection of complications. METHODS: This is a retrospective cohort study including MM patients who were diagnosed, treated, and followed in 2 institutions. These patients were studied with SS, WB-MR, and/or 18F-FDG PET/CT. We studied bone lesions by anatomical locations and analyzed the concordance between SS and a tomographic technique (WB-MR or 18F-FDG PET/CT) and between both tomographic techniques (WB-MR and PET/CT). RESULTS: Forty-four MM patients with a mean age of 62.6 years (range, 38-85 years) were included from January 2012 to February 2016. Whole-body MR and 18F-FDG PET/CT found more lesions than SS in every location except in the skull. Concordance between WB-MR and 18F-FDG PET/CT was either good or excellent in most of the locations and in plasmacytoma studies. However, WB-MR was better than 18F-FDG PET/CT in the study of complications (medullar compression and vascular necrosis). CONCLUSIONS: Our results suggest the study of MM patients should include WB-MR and/or 18F-FDG PET/CT, whereas SS is only useful for the skull. Whole-body MR and 18F-FDG PET/CT are complementary techniques, because both of them show good concordance in almost every location. It is still necessary to individualize the indication of each technique according to patient characteristics.
Asunto(s)
Fluorodesoxiglucosa F18 , Imagen por Resonancia Magnética , Mieloma Múltiple/patología , Mieloma Múltiple/terapia , Tomografía Computarizada por Tomografía de Emisión de Positrones , Esqueleto/diagnóstico por imagen , Imagen de Cuerpo Entero , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mieloma Múltiple/diagnóstico por imagen , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
INTRODUCTION: Primary progressive aphasia (PPA) is a clinical syndrome of neurodegenerative origin with 3 main variants: non-fluent, semantic, and logopenic. However, there is some controversy about the existence of additional subtypes. Our aim was to study the language and cognitive features associated with a new proposed classification for PPA. MATERIAL AND METHODS: Sixty-eight patients with PPA in early stages of the disease and 20 healthy controls were assessed with a comprehensive language and cognitive protocol. They were also evaluated with 18F-FDG positron emision tomography (PET). Patients were classified according to FDG PET regional metabolism, using our previously developed algorithm based on a hierarchical agglomerative cluster analysis with Ward's linkage method. Five variants were found, with both the non-fluent and logopenic variants being split into 2 subtypes. Machine learning techniques were used to predict each variant according to language assessment results. RESULTS: Non-fluent type 1 was associated with poorer performance in repetition of sentences and reading of irregular words than non-fluent type 2. Conversely, the second group showed a higher degree of apraxia of speech. Patients with logopenic variant type 1 performed more poorly on action naming than patients with logopenic type 2. Language assessments were predictive of PET-based subtypes in 86%-89% of cases using clustering analysis and principal components analysis. CONCLUSIONS: Our study supports the existence of 5 variants of PPA. These variants show some differences in language and FDG PET imaging characteristics. Machine learning algorithms using language test data were able to predict each of the 5 PPA variants with a relatively high degree of accuracy, and enable the possibility of automated, machine-aided diagnosis of PPA variants.
Asunto(s)
Afasia Progresiva Primaria/fisiopatología , Encéfalo/fisiología , Aprendizaje Automático , Habla , Anciano , Afasia Progresiva Primaria/diagnóstico , Femenino , Humanos , Pruebas del Lenguaje , Masculino , Persona de Mediana Edad , Habla/fisiologíaRESUMEN
OBJECTIVES: To compare staging correctness between contrast-enhanced FDG PET/ceCT and 64-slice multi-detector-row CT (ceCT64) for initial staging and response evaluation at the end of treatment (EOT) in patients with Hodgkin lymphoma, diffuse large B cell lymphoma (DLBCL), and follicular lymphoma. METHODS: This prospective study compared initial staging and response evaluation at EOT. One hundred eighty-one patients were randomly assigned to either ceCT64 or FDG PET/ceCT. A nuclear medicine physician and a radiologist read FDG PET/ceCT scans independently and achieved post hoc consensus, whereas another independent radiologist interpreted ceCT64 separately. The reference standard included all clinical information, all tests, and follow-up. Ethics committees of the participating centers approved the study, and all participants provided written consent. RESULTS: Ninety-one patients were randomized to ceCT64 and 90 to FDG PET/ceCT; 72 had Hodgkin lymphoma, 72 had DLBCL, and 37 had follicular lymphoma. There was excellent correlation between the reference standard and initial staging for both FDG PET/ceCT (κ = 0.96) and ceCT64 (κ = 0.84), although evaluation of the response at EOT was excellent only for FDG PET/ceCT (κ = 0.91). CONCLUSIONS: Our study demonstrated satisfactory agreement between FDG PET/ceCT (κ = 0.96) and ceCT64 (κ = 0.84) in initial staging compared with the reference standard (P = 0.16). Response evaluation at EOT with FDG PET/ceCT (κ = 0.91) was superior compared with ceCT64 (κ = 0.307) (P < 0.001).
Asunto(s)
Medios de Contraste , Fluorodesoxiglucosa F18 , Linfoma/diagnóstico por imagen , Linfoma/terapia , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Adulto , Anciano , Femenino , Humanos , Linfoma/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Tomografía Computarizada por Tomografía de Emisión de Positrones/instrumentación , Estudios Prospectivos , Resultado del TratamientoRESUMEN
PURPOSE: Vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor-1 (EGFR) and cyclooxygenase-2 (COX-2) stimulate key processes involved in tumour progression and are important targets for cancer therapeutics. (18)F-FDG maximum standardized uptake value (SUVmax) on PET/CT is a marker of tumour metabolic activity. The purpose of this study was to measure percentage reductions in SUVmax (∆SUVmax%), VEGFR-2 (∆VEGFR-2%), EGFR (∆EGFR%) and COX-2 (∆COX-2%) in patients with locally advanced rectal cancer (LARC) after preoperative treatment, and to correlate the changes in these markers of response with pathological response in terms of tumour regression grade (TRG) using Rödel's scale and long-term clinical outcome. METHODS: VEGFR-2, EGFR and COX-2 were measured using a quantitative and qualitative compound immunohistochemistry analysis (immunoreactive score) of the pretreatment endoscopic biopsy and definitive surgical specimens. Composite indexes using ∆SUVmax% and the three molecules were developed to differentiate patients with metabolic and molecular responses from nonresponders. Cox proportional hazards model was used to explore associations between the tumour markers, disease-free survival (DFS) and overall survival (OS). RESULTS: The analysis included 38 patients with a median follow-up of 86 months (range 5 - 113 months). The ∆VEGFR-2%/∆SUVmax% index correctly identified 13 of 19 pathological responders (TRG 3 and 4) and 17 of 19 nonresponders (TRG 0 - 2) (sensitivity 68 %, specificity 89 %, accuracy 79 %, positive predictive value 87 %, negative predictive value 74 %). In multivariate analysis, only the ∆VEGFR-2%/∆SUVmax% index was associated with DFS (HR 0.11, p = 0.001) and OS (HR 0.15, p = 0.02). CONCLUSION: In patients with LARC the ∆VEGFR-2%/∆SUVmax% response index is associated with outcome. Determination of the optimal diagnostic cut-off level for this novel biomarker association should be explored. Evaluation in a clinical trial is required to determine whether selected patients could benefit from treatment with a VEGFR-targeted therapeutic agent.
Asunto(s)
Terapia Neoadyuvante , Neoplasias del Recto/metabolismo , Neoplasias del Recto/terapia , Adulto , Anciano , Ciclooxigenasa 2/metabolismo , Supervivencia sin Enfermedad , Receptores ErbB/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Tomografía de Emisión de Positrones , Neoplasias del Recto/patología , Resultado del Tratamiento , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismoRESUMEN
An experience with an automated infuser device at a university hospital is presented in this paper. Occupational doses at operators' fingertips were measured using optically stimulated luminescence dosemeters for two different scenarios: (i) using a semi-automatic system to prepare the fluorodesoxiglucose (FDG) injections that were delivered to the patient manually and (ii) using an automated infusion device that prepares and delivers the FDG dose. The accuracy of the activity prepared by the automatic system was also verified. Reductions in fingertip doses of 60 % using the fully automatic system have been measured. The difference between the programmed and the delivered activity was 2 %. The use of the automatic infuser in the authors' institution has led to a substantial reduction in hand radiation doses. But contamination risks, even though reduced, still exist; therefore, radioisotope manipulation should follow strict radiation protection rules to avoid incidents. Improved accuracy in dose delivery reduces chances of dose misadministration.
Asunto(s)
Fluorodesoxiglucosa F18/administración & dosificación , Infusiones Intravenosas , Imagen Multimodal/métodos , Tomografía de Emisión de Positrones/métodos , Dosis de Radiación , Radiofármacos/administración & dosificación , Tomografía Computarizada por Rayos X/métodos , Automatización , Diseño de Equipo , Dedos , Humanos , Imagenología Tridimensional/métodos , Tomografía de Emisión de Positrones/instrumentación , Radioisótopos , Radiometría/métodos , Reproducibilidad de los Resultados , Piel/efectos de la radiaciónRESUMEN
PURPOSE: It has long been debated whether human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) are associated with rectal cancer. The gene products of HCMV and EBV contribute to cell-cycle progression, mutagenesis, angiogenesis and immune evasion. The aim of this prospective study was to analyse the association between infection of a tumour by HCMV and EBV and clinical, histological, metabolic ((18)F-FDG uptake), volumetric (from CT) and molecular (KRAS status) features and long-term outcomes in a homogeneously treated group of patients with locally advanced rectal cancer. METHODS: HCMV and EBV were detected in pretreatment biopsies using polymerase chain reaction (PCR). The Cox proportional hazards regression model was used to explore associations between viral infection and disease-free survival (DFS) and overall survival (OS). RESULTS: We analysed 37 patients with a median follow-up of 74 months (range 5-173 months). Locoregional control, OS and DFS at 5 years were 93%, 74% and 71%, respectively. Patients with HCMV/EBV coinfection had a significantly higher maximum standardized uptake value than patients without viral coinfection (p = 0.02). Significant differences were also observed in staging and percentage relative reduction in tumour volume between patients with and without HCMV infection (p < 0.01) and EBV infection (p < 0.01). KRAS wildtype status was significantly more frequently observed in patients with EBV infection (p <0.01) and HCMV/EBV co-infection (p = 0.04). No significant differences were observed in OS or DFS between patients with and without EBV infection (p = 0.88 and 0.73), HCMV infection (p = 0.84 and 0.79), and EBV/CMV coinfection (p = 0.24 and 0.39). CONCLUSION: This pilot study showed that viral infections were associated with metabolic staging differences, and differences in the evolution of metabolic and volumetric parameters and KRAS mutations. Further findings of specific features will help determine the best candidates for metabolic and volumetric staging and restaging. Further toxicity profile findings will help to determine the best candidates for specific supportive treatment during pelvic chemoradiotherapy in patients with locally advanced rectal cancer.
Asunto(s)
Infecciones por Citomegalovirus/diagnóstico por imagen , Infecciones por Virus de Epstein-Barr/diagnóstico por imagen , Fluorodesoxiglucosa F18 , Tomografía de Emisión de Positrones , Radiofármacos , Neoplasias del Recto/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adulto , Anciano , Quimioradioterapia , Infecciones por Citomegalovirus/complicaciones , Infecciones por Virus de Epstein-Barr/complicaciones , Femenino , Fluorodesoxiglucosa F18/farmacocinética , Humanos , Masculino , Persona de Mediana Edad , Imagen Multimodal , Terapia Neoadyuvante , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas p21(ras) , Radiofármacos/farmacocinética , Neoplasias del Recto/complicaciones , Neoplasias del Recto/genética , Neoplasias del Recto/terapia , Proteínas ras/genéticaRESUMEN
PURPOSE: Vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor-1 (EGFR), and cyclooxygenase-2 (COX-2) stimulate key processes involved in tumor progression and are important targets for cancer drugs. (18)F-FDG maximum standardized uptake value (SUVmax) is a marker of tumor metabolic activity. The purpose of this study was to measure SUVmax combined with VEGFR-2, EGFR and COX-2 proteins in pretreatment tumor biopsies from patients with locally advanced rectal cancer receiving intensive neoadjuvant treatment and to correlate the findings with clinical outcome. METHODS: VEGFR-2, EGFR and COX-2 were measured using the immunoreactive score (IRS). SUVmax (median 8.4) was quantified in tumors with molecular overexpression (IRS ≥3 + SUVmax ≥ 8.4 indicating active tumors; SUVmax <8.4 indicating inactive tumors). The Cox proportional hazards model was used to explore associations between tumor markers, disease-free survival (DFS) and overall survival (OS). RESULTS: The study group comprised 38 patients with a median follow-up of 69.3 months (range 4.5 - 92 months). Multivariate analysis showed that active tumors (overexpressing VEGFR-2, high SUVmax) were associated with worse DFS (HR 4.73, 95 % CI 1.18 - 22.17; p = 0.04) and OS (HR 4.28, 95 % CI 1.04 - 20.12; p = 0.05). CONCLUSION: Active tumors overexpressing VEGFR-2 are associated with a worse overall outcome in patients with rectal cancer treated with induction chemotherapy followed by pelvic chemoradiation and surgery. The optimal diagnostic cut-off level for this novel biomarker association should be investigated. Evaluation in a clinical trial is required to determine whether selected patients could benefit from a VEGFR-targeting drug.
Asunto(s)
Adenocarcinoma/diagnóstico , Biomarcadores de Tumor/metabolismo , Terapia Neoadyuvante , Tomografía de Emisión de Positrones , Neoplasias del Recto/diagnóstico , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/terapia , Adulto , Anciano , Quimioradioterapia Adyuvante , Ciclooxigenasa 2/genética , Ciclooxigenasa 2/metabolismo , Receptores ErbB/genética , Receptores ErbB/metabolismo , Femenino , Fluorodesoxiglucosa F18/farmacocinética , Humanos , Masculino , Persona de Mediana Edad , Imagen Multimodal , Valor Predictivo de las Pruebas , Radiofármacos/farmacocinética , Neoplasias del Recto/diagnóstico por imagen , Neoplasias del Recto/terapia , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Receptor 2 de Factores de Crecimiento Endotelial Vascular/genéticaRESUMEN
PURPOSE: To prospectively evaluate the usefulness of (18)F-FDG PET/CT) imaging for predicting histopathological response and long-term clinical outcomes in locally advanced rectal cancer (LARC). METHODS: This prospective study included 38 patients with a confirmed diagnosis of LARC (cT3-4 or cN+) who underwent (18)F-FDG PET/CT before and after neoadjuvant therapy (NAT). Total mesorectal excision was scheduled 6 weeks after NAT and was followed by an expert histopathological analysis of the surgical specimen. Baseline variables and previously identified maximum FDG standardized uptake value (SUVmax) cut-off values before NAT (SUVmaxPRE ≥6) and after NAT (SUVmaxPOST ≥2), and the absolute and percentage reductions from baseline SUVmax (∆SUVmax <4 and ∆SUVmax% <65 %, respectively) were applied to differentiate patients showing a metabolic tumour response from nonresponders. These features were correlated with tumour regression grade (TRG), disease-free survival (DFS) and overall survival (OS). RESULTS: Significantly higher 5-year DFS and OS were seen in 19 responders (TRG 3 or 4) than in 19 nonresponders (TRG 0-2; 94.4 vs. 48.8 %, p = 0.001; 94.7 vs. 63.2 %, p = 0.02, respectively). In multivariate analysis the only PET/CT SUVmax-based parameter significantly correlated with the likelihood of recurrence and survival was ∆SUV% <65 % (HR = 5.95, p = 0.02, for DFS; HR = 5.26, p = 0.04, for OS) CONCLUSION: This prospective study proved that (18)F-FDG PET/CT is a valuable imaging tool for assessing rectal cancer TRG and long-term prognosis, and could potentially serve as an intermediate endpoint in treatment optimization research and rectal cancer patient care.
Asunto(s)
Fluorodesoxiglucosa F18 , Imagen Multimodal , Tomografía de Emisión de Positrones , Neoplasias del Recto/diagnóstico por imagen , Neoplasias del Recto/terapia , Tomografía Computarizada por Rayos X , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Neoplasias del Recto/metabolismo , Neoplasias del Recto/patología , Reproducibilidad de los Resultados , Factores de Tiempo , Resultado del TratamientoRESUMEN
BACKGROUND: Radiation-induced brain injury (RBI) and low-perfusion brain syndromes are mediated by ischemia and hypometabolism and have limited treatment options. Ozone therapy as treatment in vascular diseases has been described, but the effects on brain tissue have not been well documented. CASE REPORT: We describe a 75-year-old patient with vascular risk factors and meningioma who was treated with stereotactic radiosurgery. 14 months later the patient presented with progressive clinical impairment despite the use of acetylsalicylic acid and corticosteroids. Clinical and imaging evaluations before/after ozone therapy were done by magnetic resonance imaging (MRI), computed tomography (CT), single photon emission computed tomography (SPECT), and positron emission tomography (PET); performance status assessment was done using Barthel Index and World Health Organization/Eastern Cooperative Oncology Group Scale (WHO/ECOG Scale). Ozone therapy was performed by autohemotransfusion. RESULTS: Basal images showed brain areas with ischemia and hypometabolism compatible with ischemic processes and/or RBI. There were no changes in MRI or CT scan images following ozone therapy. However, improvements in brain perfusion and metabolism were demonstrable with SPECT and PET; they correlated with clinical development and performance status scales. CONCLUSION: This report supports our previous works about the effect of ozone therapy in cerebral blood flow, and it suggests the use of ozone therapy in ischemic and hypometabolic brain syndromes such as stroke or RBI.
Asunto(s)
Isquemia Encefálica/terapia , Encéfalo , Ozono/farmacología , Ozono/uso terapéutico , Flujo Sanguíneo Regional/efectos de los fármacos , Anciano , Encéfalo/irrigación sanguínea , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Femenino , Humanos , Tomografía de Emisión de Positrones , Resultado del TratamientoRESUMEN
PURPOSE: Radiation-induced brain injury (RBI) is an insidious side-effect of radiotherapy mediated by vascular alterations, inflammation and ischaemia. In previous studies we had shown potential increases in loco-regional blood flow and glucose metabolism in brain tumours by using electrical cervical spinal cord stimulation (SCS). In this preliminary report we demonstrate the effect of cervical SCS on RBI-tissue metabolism, as assessed using [(18)F]fluorodeoxyglucose-positron emission tomography (FDG-PET). METHODS: SCS devices were inserted in eight patients with diagnosis of potential RBI in previously irradiated areas. While the SCS device was deactivated, each patient underwent an initial FDG-PET study to evaluate the clinical status. A second FDG-PET study was performed later the same day while the SCS device was activated in order to evaluate the effect of cervical SCS on glucose metabolism. RESULTS: Basal glucose metabolism in RBI areas was 31% lower than peri-RBI areas (p = 0.009) and 32% lower than healthy contra-lateral areas (p = 0.020). There was a significant increase in glucose uptake during SCS in both the RBI (p = 0.005) and the peri-RBI (p = 0.004) areas, with measured increases of 38 and 42%, respectively. The estimated potential maximal residual activity of the first FDG dose's contribution to the activity on the second scan was Asunto(s)
Daño Encefálico Crónico/metabolismo
, Encéfalo/metabolismo
, Glucosa/metabolismo
, Traumatismos por Radiación/metabolismo
, Radioterapia/efectos adversos
, Médula Espinal/fisiología
, Adulto
, Vías Aferentes/fisiología
, Anciano
, Encéfalo/diagnóstico por imagen
, Encéfalo/fisiopatología
, Daño Encefálico Crónico/diagnóstico por imagen
, Daño Encefálico Crónico/fisiopatología
, Mapeo Encefálico/métodos
, Neoplasias Encefálicas/radioterapia
, Circulación Cerebrovascular/fisiología
, Vértebras Cervicales
, Estimulación Eléctrica/métodos
, Metabolismo Energético/fisiología
, Femenino
, Fluorodesoxiglucosa F18
, Glucosa/análisis
, Humanos
, Masculino
, Persona de Mediana Edad
, Tomografía de Emisión de Positrones/métodos
, Valor Predictivo de las Pruebas
, Traumatismos por Radiación/diagnóstico por imagen
, Traumatismos por Radiación/fisiopatología
, Sensibilidad y Especificidad
RESUMEN
OBJECTIVE: Syndromes resulting from decreased cerebral blood flow and metabolic activity have significant clinical and social repercussion. However, treatment options are limited. Cervical spinal cord stimulation has shown clinical benefit in the management of several ischemic syndromes. The aim of this report was to assess the effect of cervical spinal cord stimulation on cerebral glucose metabolism. MATERIALS AND METHODS: Between April 2000 and December 2005, 16 patients with brain tumors were assessed. Before and during spinal cord stimulation, they had cerebral glucose metabolism evaluated using 18fluoro-2-deoxyglucose positron emission tomography (18FDG-PET) in the healthy cerebral hemisphere contralateral to the lesion area. RESULTS: Following cervical spinal cord stimulation, there was a significant (p<0.001) increase in glucose metabolism in healthy cerebral hemisphere. The measured increase was 37.7%, with an estimated potential maximal contribution of the first 18fluoro-2-deoxyglucose injection to the quantification of the second positron emission tomography study (carry-over effect)Asunto(s)
Glucemia/metabolismo
, Neoplasias Encefálicas/diagnóstico por imagen
, Neoplasias Encefálicas/terapia
, Terapia por Estimulación Eléctrica
, Médula Espinal/efectos de la radiación
, Adulto
, Neoplasias Encefálicas/irrigación sanguínea
, Femenino
, Fluorodesoxiglucosa F18
, Humanos
, Masculino
, Persona de Mediana Edad
, Tomografía de Emisión de Positrones/métodos
, Estudios Retrospectivos
, Médula Espinal/fisiopatología
RESUMEN
UNLABELLED: Detection of the primary tumor has a key role in the management of patients with unknown primary tumors (UPT). The aim of this study was to perform a meta-analysis of the literature to evaluate the accuracy of (18)F-FDG PET in primary tumor detection in patients with UPT. METHODS: Systematic methods were used to identify, select, and evaluate the methodologic quality of the studies as well as to summarize the overall findings of sensitivity, specificity, and detection capacity of the primary tumor. The search strategy consisted of identifying studies published between January 1994 and May 2001 indexed in MEDLINE and CANCERLIT. Studies identified by manually searching reference lists of retrieved studies or by reviewing abstracts from recent conference proceedings were also included. Inclusion criteria were studies that evaluated primary tumor detection with (18)F-FDG PET in patients with UPT. Exclusion criteria were duplicated studies or those outdated by subsequent ones. The statistical analysis included 95% confidence intervals (CI) of sensitivity and specificity, both in the pooled data and in the types of studies found. Variation in accuracy between studies was analyzed calculating the natural logarithm of the odds ratio (ln OR) due to study characteristics. Funnel plots of sensitivity and specificity and the summary receiver-operating-characteristic (ROC) curve were also represented. RESULTS: Fifteen studies met the inclusion criteria and were analyzed. Although sample sizes were small, compliance with the methodologic quality criteria was adequate. Heterogeneity analysis showed that differences in the study quality did not correlate with differences in study results. The 95% CI of sensitivity and specificity presented global homogeneity, estimating the sensitivity at 0.87 (95% CI, 0.81-0.92) and the specificity at 0.71 (95% CI, 0.64-0.78). The summary ROC curve showed a good relationship between sensitivity and specificity. The ln OR presented significant values in >75% of the studies. CONCLUSION: (18)F-FDG PET could be useful in patients with UPT for the detection of the primary tumor. (18)F-FDG PET has intermediate specificity and high sensitivity, indicating the existence of few false-negative results, an important feature in the management of oncologic patients that could suggest its utility in the initial stages of the management process.