Comparação entre ressonância magnética de corpo inteiro com 18F-FDG PET/CT no estadiamento M de câncer de pulmão em área endêmica de doença granulomatosa

Abstract

Introduction: 18F-FDG PET/CT is the currently method chosen to assessment distant metastatic lesions in lung cancer patients. However, this method has some limitation to evaluate tissues with high metabolic activity such sites of ongoing inflammation and infections. In contrast, whole-body magnetic resonance imaging (WB-MRI) with diffusion weighted imaging (DWI) has demonstrated comparable diagnostic performance to 18F-FDG PET/CT in M-stage. There are no studies comparing both methods together in an endemic area of granulomatous disease. Objective: To evaluate the role of WB-MRI with DWI in the M-staging of patients with lung cancer confirmed by biopsy in an endemic region of granulomatous disease, and to compare these findings to those determined by the gold standard method 18F-FDG PET/CT. We also aimed to evaluate the prevalence of secondary metastases derived from the lung cancer in this geographic context. Methods: This was a retrospective multicentric cross-sectional study, with consecutive enrollment of 97 patients from April 2011 to December 2019. Patients selected for this study had confirmed histologic diagnosis of lung cancer, were over 18 years old, underwent 18F-FDG PET/CT and WB-MRI with DWI for initial staging of lung cancer with maximum interval of 10 days between methods, and received no previous cancer treatment. Demographics and clinical data of participants were collected. Thereafter, TNM stage assessment was determined by using the 8th TNM edition by for each method separately, in an interval of 4 weeks. Images were examined by 2 experienced physicians, blinded to the clinical information and alternative imaging results from participants. The final M-staging and presence of metastatic lesion was determined based on imaging analyses of the lesion during a 6-month follow-up period. A panel consensus method was used as a standard reference to calculate the diagnosis accuracy of both techniques for each patient. Receiver operating characteristic (ROC) analysis and McNemar test were used to compare the efficacy between exams. Results: Seventy-seven patients were evaluated in this study. The cohort was predominantly male (62.3%), of older age (mean 66.1 years ± 9.8; range, range 42 - 68), and largely smoker, which corresponded to 84.4%. Thirty-five of 76 patients (46%) had metastatic lesions. Accuracy for detecting metastases was 81.6% (62 of 76 patients) for WB-MRI with DWI, and 72.4% (55 of 76 patients) for 18F-FDG PET/CT (P  0.05). Although the differences were not statistically significant, WB-MRI was more useful for detecting brain and bones metastases. Both methods described a higher number of patients in advanced-stages of lung cancer (over 60% 8 in Stage III and IV). T and N stage descriptors showed similar results for both techniques, except for N3 where WB-MRI with DWI found five more patients than 18-F FDG PET/CT. Conclusions: Both WB-MRI with DWI and 18-F FDG PET/CT imaging methods demonstrated acceptable accuracy for M-staging in lung cancer patients in an endemic region of granulomatosis disease. Additionally, this study highlighted de high prevalence of advance-stage lung cancer patients in this geographic region.