Pilot Study of [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET)/Magnetic Resonance Imaging (MRI) for Staging of Muscle-invasive Bladder Cancer (MIBC).

INTRODUCTION: Computed tomography (CT) has limited diagnostic accuracy for staging of muscle-invasive bladder cancer (MIBC). [18F] Fluorodeoxyglucose positron emission tomography (FDG-PET)/magnetic resonance imaging (MRI) is a novel imaging modality incorporating functional imaging with improved soft tissue characterization. This pilot study evaluated the use of preoperative FDG-PET/MRI for staging of MIBC. PATIENTS AND METHODS: Twenty-one patients with MIBC with planned radical cystectomy were enrolled. Two teams of radiologists reviewed FDG-PET/MRI scans to determine: (1) presence of primary bladder tumor; and (2) lymph node involvement and distant metastases. FDG-PET/MRI was compared with cystectomy pathology and computed tomography (CT). RESULTS: Eighteen patients were included in the final analysis, most (72.2%) of whom received neoadjuvant chemotherapy. Final pathology revealed 10 (56%) patients with muscle invasion and only 3 (17%) patients with lymph node involvement. Clustered analysis of FDG-PET/MRI radiology team reads revealed a sensitivity of 0.80 and a specificity of 0.56 for detection of the primary tumor with a sensitivity of 0 and a specificity of 1.00 for detection of lymph node involvement when compared with cystectomy pathology. CT imaging demonstrated similar rates in evaluation of the primary tumor (sensitivity, 0.91; specificity, 0.43) and lymph node involvement (sensitivity, 0; specificity, 0.93) when compared with pathology. CONCLUSIONS: This pilot single-institution experience of FDG-PET/MRI for preoperative staging of MIBC performed similar to CT for the detection of the primary tumor; however, the determination of lymph node status was limited by few patients with true pathologic lymph node involvement. Further studies are needed to evaluate the potential role for FDG-PET/MRI in the staging of MIBC.

Examination and prognostic implications of the unique microenvironment of breast cancer brain metastases.

PURPOSE: Brain metastases (BM) are a complication of advanced breast cancer (BC). Histology of melanoma BM offers prognostic value; however, understanding the microenvironment of breast cancer brain metastases (BCBM) is less characterized. This study reports on four histological biomarkers, gliosis, immune infiltrate, hemorrhage, necrosis, and their prognostic significance in BCBM. METHODS: A biobank of 203 human tissues from patients who underwent craniotomy for BCBM was created across four academic institutions. Degree of gliosis, immune infiltrate, hemorrhage, and necrosis were identified and scored via representative H&E stain (0-3+). Overall survival (OS) was estimated using the Kaplan-Meier method. Cox proportional hazards regression evaluated prognostic value of the biomarkers in the context of standard clinical characteristics. RESULTS: BCBM subtype (available for n = 158) was 36% Her2+, 26% hormone receptor (HR)+/Her2- 38% HR-/Her2- (triple negative, TN). Gliosis was observed in 82% (116/141) of BCBM, with immune infiltrate 44% (90/201), hemorrhage 82% (166/141), and necrosis 87% (176/201). Necrosis was significantly higher in TNBC (p < 0.01). Presence of gliosis, immune infiltrate, and hemorrhage correlated with improved OS (p = 0.03, p = 0.03, p = 0.1), while necrosis correlated with inferior OS (p = 0.01). Improved OS was associated with gliosis in TN (p = 0.02), and immune infiltrate (p = 0.001) and hemorrhage (p = 0.07) in HER2+. In a multivariable model for OS, incorporating these biomarkers with traditional clinical variables improved the model fit (p < 0.001). CONCLUSION: Gliosis confers superior prognosis in TNBC BM; immune infiltrate and hemorrhage correlate with superior prognosis in HER2+ BCBM. Understanding the metastatic microenvironment of BCBM refines prognostic considerations and may unveil novel therapeutic strategies.