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Purpose: This study describes oncological outcomes and investigates prognostic factors for patients with gliosarcomas (GSM). Methods: Histopathologically confirmed GSM patients who underwent treatment at five European institutions were retrospectively analyzed. Results: We analyzed 170 patients with a median clinical follow‐up time of 9.2 months. The majority received surgery (94.1%), postoperative radiotherapy (pRT, 81.8%), and temozolomide (TMZ)‐based postoperative chemotherapy (66.5%). The median overall survival (OS) and progression‐free survival (PFS) were 12.3 and 6.6 months, respectively. In the multivariable Cox regression analysis (MVA), the following factors were significantly associated with OS: age per year (hazard ratio (HR): 1.03, p < 0.001), subtotal resection (STR) versus biopsy only (HR: 0.15, p = 0.018), gross total resection (GTR) versus biopsy only (HR: 0.13, p = 0.011), pRT versus no pRT (HR: 0.20, p < 0.001), postoperative TMZ‐based chemotherapy versus no postoperative chemotherapy (HR: 0.44, p = 0.003), MGMT promoter non‐methylated versus methylated (HR: 1.79, p = 0.05), and tumor diameter per cm (HR: 1.15, p = 0.046). For PFS, the following factors were significantly associated in the MVA: GTR versus biopsy only (HR: 0.19, p = 0.026), pRT versus no pRT (HR: 0.36, p = 0.006), postoperative TMZ‐based chemotherapy vs. no postoperative chemotherapy (HR: 0.39, p < 0.001), MGMT promoter status unknown versus methylated (HR: 1.69, p = 0.034), and tumor diameter per cm (HR: 1.18, p = 0.016). Sex, primary or secondary GSM, and TP53 mutational status were not significantly associated with OS or PFS. Conclusions: Trimodal therapy comprising surgical resection, pRT and TMZ‐based chemotherapy appears to have the most beneficial effect on survival in GSM patients. Smaller tumor size, younger age and methylated MGMT promoters are associated with improved survival. To our knowledge, this is the largest multi‐institutional cohort study investigating outcomes and prognostic factors for GSM. [ABSTRACT FROM AUTHOR]

Background: Quantitative image analysis based on radiomic feature extraction is an emerging field for survival prediction in oncological patients. 18F-Fluorethyltyrosine positron emission tomography (18F-FET PET) provides important diagnostic and grading information for brain tumors, but data on its use in survival prediction is scarce. In this study, we aim at investigating survival prediction based on multiple radiomic features in glioblastoma patients undergoing radio(chemo)therapy.Methods: A dataset of 37 patients with glioblastoma (WHO grade 4) receiving radio(chemo)therapy was analyzed. Radiomic features were extracted from pre-treatment 18F-FET PET images, following intensity rebinning with a fixed bin width. Principal component analysis (PCA) was applied for variable selection, aiming at the identification of the most relevant features in survival prediction. Random forest classification and prediction algorithms were optimized on an initial set of 25 patients. Testing of the implemented algorithms was carried out in different scenarios, which included additional 12 patients whose images were acquired with a different scanner to check the reproducibility in prediction results.Results: First order intensity variations and shape features were predominant in the selection of most important radiomic signatures for survival prediction in the available dataset. The major axis length of the 18F-FET-PET volume at tumor to background ratio (TBR) 1.4 and 1.6 correlated significantly with reduced probability of survival. Additional radiomic features were identified as potential survival predictors in the PTV region, showing 76% accuracy in independent testing for both classification and regression.Conclusions: 18F-FET PET prior to radiation provides relevant information for survival prediction in glioblastoma patients. Based on our preliminary analysis, radiomic features in the PTV can be considered a robust dataset for survival prediction. [ABSTRACT FROM AUTHOR]

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Purpose/background: [F]fluoroethylcholine (FECH) has been shown to be a valuable PET-tracer in recurrent prostate cancer (PCa), but still has limited accuracy. RM2 is a gastrin-releasing peptide receptor (GRPr) antagonist that binds to GRPr on PCa cells. Recent studies suggest that GRPr imaging with PET/CT is a promising technique for staging and restaging of PCa. We explore the value of GRPr-PET using the Ga-labeled GRPr antagonist RM2 in a selected population of patients with biochemically recurrent PCa and a negative/inconclusive FECH-PET/CT. Material and methods: In this retrospective study 16 men with biochemical PCa relapse and negative ( n = 14) or inconclusive ( n = 2) FECH-PET/CT underwent whole-body Ga-RM2-PET/CT. Mean time from FECH-PET/CT to Ga-RM2-PET/CT was 6.1 ± 6.8 months. Primary therapies in these patients were radical prostatectomy ( n = 13; 81.3%) or radiotherapy ( n = 3; 18.7%). 14/16 patients (87.5%) had already undergone salvage therapies because of biochemical relapse prior to Ga-RM2-PET/CT imaging. Mean ± SD PSA at Ga-RM2-PET/CT was 19.4 ± 53.5 ng/ml (range 1.06-226.4 ng/ml). Results: Ga-RM2-PET/CT showed at least one region with focal pathological uptake in 10/16 patients (62.5%), being suggestive of local relapse ( n = 4), lymph node metastases (LNM; n = 4), bone metastases ( n = 1) and lung metastasis with hilar LNM ( n = 1). Seven of ten positive Ga-RM2 scans were positively confirmed by surgical resection and histology of the lesions ( n = 2), by response to site-directed therapies ( n = 2) or by further imaging ( n = 3). Patients with a positive Ga-RM2-scan showed a significantly higher median PSA (6.8 ng/ml, IQR 10.2 ng/ml) value than those with a negative scan (1.5 ng/ml, IQR 3.1 ng/ml; p = 0.016). Gleason scores or concomitant antihormonal therapy had no apparent impact on the detection of recurrent disease. Conclusion: Even in this highly selected population of patients with known biochemical recurrence but negative or inconclusive FECH-PET/CT, a Ga-RM2-PET/CT was helpful to localize PCa recurrence in the majority of the cases. Thus, Ga-RM2-PET/CT deserves further investigation as a promising imaging modality for imaging PCa recurrence. [ABSTRACT FROM AUTHOR]