Valor do FDG[18F]-PET/TC como preditor de câncer em nódulo pulmonar solitário

Abstract

Objective: To determine the diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) using fluorine-18-deoxyglucose ([18F]-FDG) for the evaluation of a solitary pulmonary nodule (SPN). Methods: Prospective analysis of 53 consecutive patients submitted to PET/CT between March 2005 and May 2007 for the evaluation of an SPN. Of those, 32 met the criteria for inclusion in the present study. The lesions were evaluated for location, size, radiotracer uptake and maximum standardized uptake value (SUV). The FDG-PET/CT results were correlated with other predictors of malignancy (age, gender, smoking status, nodule size and nodule location). The definitive diagnosis was established through histopathology or through clinical/radiological follow-up for at least one year. Results: Fourteen malignant SPNs were found. Through analysis of the receiver operating characteristic curve, we established an SUV of 2.5 as the most appropriate cut-off point, since it correctly identified 13 of the 14 malignant SPNs. The results below that point revealed one false positive for neoplasia out of a total of 14. The semiquantitative method presented a sensitivity of 92.9%, specificity of 72.2%, positive predictive value of 72.2%, negative predictive value of 92.9% and accuracy of 81.2%. The multivariate analysis showed a statistically significant association with SPN malignancy only for nodule location in the upper lobes (p = 0.048) and SUV (p = 0.007). Conclusions: The results obtained suggest that the SUV of [18F]-FDG is a useful predictor of neoplasia in SPN, with a high negative predictive value, which allows malignancy to be safely ruled out, showing its relevance in the diagnostic approach to pulmonary nodules.Keywords: Positron-emission tomography; Coin lesion, pulmonary; Lung neoplasms. ResumoObjetivo: Determinar a acurácia diagnóstica da positron emission tomography (tomografia por emissão de pósitrons)/tomografia computadorizada (PET/TC) com deoxiglicose marcada com flúor-18, conhecida como fluorodeoxiglicose (FDG[18F]), na avaliação de nódulo pulmonar solitário (NPS). Métodos: Análise prospectiva de 53 pacientes consecutivos que realizaram PET/TC para avaliação de NPS, entre março de 2005 e maio de 2007. Destes 32 preencheram os critérios de inclusão. As lesões foram avaliadas quanto a sua localização e tamanho, grau de captação do radiofármaco e o standardized uptake value (SUV, valor padronizado de captação) máximo das lesões. Os achados dos estudos de FDG-PET/TC foram correlacionados com outros preditores de malignidade (idade, sexo, tabagismo, tamanho e localização do nódulo). O diagnóstico definitivo foi estabelecido por confirmação histopatológica ou acompanhamento clínico-radiológico por um período mínimo de um ano. Resultados: Encontrados 14 NPS malignos. Após análise da curva ROC, o SUV de 2,5 foi considerado o melhor ponto de corte que identificou corretamente 13 dos 14 NPS malignos. Os resultados abaixo deste ponto de corte mostraram um exame falso positivo para neoplasia num total de 14....

The diagnostic accuracy of integrated positron emission tomography/computed tomography in the evaluation of pulmonary mass lesions in a tuberculosis-endemic area

“…[10] In Brazil, with a TB incidence rate of 66/100 000 population, the sensitivity and specificity of PET-CT (using an SUV max cutoff of 2.5) were found to be 92.9% and 72.2%, respectively. [11] Limited data exist for the evaluation of PET-CT in other TB-endemic areas. In a Chinese population this modality was found to have a sensitivity and specificity of 88.3% and 61.1%, respectively.…”

Solitary pulmonary nodule and 18F-FDG PET/CT. Part 2: accuracy, cost-effectiveness, and current recommendations

“…In a prospective study conducted in Rio de Janeiro, Martins et al included 32 patients and obtained results that differed from those of other studies performed in areas endemic for tuberculosis. The authors reported a 40.6% prevalence of malignancy and, using an SUVmax cut-off point of 2.5, obtained 92.9% sensitivity, 72.2% specificity, 72.2% PPV, 92.9% NPV, and 81.2% accuracy ( 15 ) .…”

Integrated PET/CT in the Staging of NSCLC

“…With integrated PET/CT, additional certainty to the presence or absence of FDG uptake in the pulmonary nodule can be achieved because morphologic CT criteria and metabolical PET criteria are available simultaneously [23]. Kim et al reported a sensitivity of 97% and a specificity of 85% for the detection of SPNs, concluding that the combination of the anatomical and metabolic images preserves the sensitivity of the CT and the specificity of the PET scan, but improves significantly the overall accuracy [24,25].…”