Can whole-body MRI replace CT in management of metastatic testicular cancer? A prospective, non-inferiority study.

PURPOSE: Concerns of imaging-related radiation exposure in young patients with high survival rates have increased the use of magnetic resonance imaging (MRI) in testicular cancer (TC) stage I. However, computed tomography (CT) is still preferred for metastatic TC. The purpose of this study was to compare whole-body MRI incl. diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) with contrast-enhanced, thoracoabdominal CT in metastatic TC. METHODS: A prospective, non-inferiority study of 84 consecutive patients (median age 33 years) with newly diagnosed metastatic TC (February 2018-January 2021). Patients had both MRI and CT before and after treatment. Anonymised images were reviewed by experienced radiologists. Lesion malignancy was evaluated on a Likert scale (1 benign-4 malignant). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated on patient and lesion level. The primary outcome was demonstrating non-inferiority regarding sensitivity of MRI compared to CT. The non-inferiority margin was set at 5%. ROC curves and interobserver agreement were calculated. RESULTS: On patient level, MRI had 98% sensitivity and 75% specificity compared to CT. On lesion level within each modality, MRI had 99% sensitivity and 78% specificity, whereas CT had 98% sensitivity and 88% specificity. MRI sensitivity was non-inferior to CT (difference 0.57% (95% CI - 1.4-2.5%)). The interobserver agreement was substantial between CT and MRI. CONCLUSION: MRI with DWIBS was non-inferior to contrast-enhanced CT in detecting metastatic TC disease. TRIAL REGISTRATION: www. CLINICALTRIALS: gov NCT03436901, finished July 1st 2021.

18F-FDG PET/CT for Very Early Response Evaluation Predicts CT Response in Erlotinib-Treated Non-Small Cell Lung Cancer Patients: A Comparison of Assessment Methods.

The purpose of this study was to determine which method for early response evaluation with 18F-FDG PET/CT performed most optimally for the prediction of response on a later CT scan in erlotinib-treated non-small cell lung cancer patients. Methods:18F-FDG PET/CT scans were obtained before and after 7-10 d of erlotinib treatment in 50 non-small cell lung cancer patients. The scans were evaluated using a qualitative approach and various semiquantitative methods including percentage change in SUVs, lean body mass-corrected (SUL) SULpeak, SULmax, and total lesion glycolysis (TLG). The PET parameters and their corresponding response categories were compared with the percentage change in the sum of the longest diameter in target lesions and the resulting response categories from a CT scan obtained after 9-11 wk of erlotinib treatment using receiver-operating-characteristic analysis, linear regression, and quadratic-weighted κ. Results: TLG delineation according to the PERCIST showed the strongest correlation to sum of the longest diameter (R = 0.564, P < 0.001), compared with SULmax (R = 0.298, P = 0.039) and SULpeak (R = 0.402, P = 0.005). For predicting progression on CT, receiver-operating-characteristic analysis showed area under the curves between 0.79 and 0.92, with the highest area under the curve of 0.92 (95% confidence interval [CI], 0.84-1.00) found for TLG (PERCIST). Furthermore, the use of a cutoff of 25% change in TLG (PERCIST) for both partial metabolic response and progressive metabolic disease, which is the best predictor of the CT response categories, showed a κ-value of 0.53 (95% CI, 0.31-0.75). This method identifies 41% of the later progressive diseases on CT, with no false-positives. Visual evaluation correctly categorized 50%, with a κ-value of 0.47 (95% CI, 0.24-0.70). Conclusion: TLG (PERCIST) was the optimal predictor of response on later CT scans, outperforming both SULpeak and SULmax The use of TLG (PERCIST) with a 25% cutoff after 1-2 wk of treatment allows us to safely identify 41% of the patients who will not benefit from erlotinib and stop the treatment at this time.

Early Change in FDG-PET Signal and Plasma Cell-Free DNA Level Predicts Erlotinib Response in EGFR Wild-Type NSCLC Patients.

INTRODUCTION: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are a treatment option in the second- or third-line palliative setting in EGFR wild-type (wt) non-small cell lung cancer (NSCLC) patients. However, response rates are low, and only approximately 25% will achieve disease control. Early prediction of treatment resistance could accelerate discontinuation of ineffective treatment and reduce unnecessary toxicity. In this study, we evaluated early changes on 18F-fluoro-D-glucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) and in total plasma cell-free DNA (cfDNA) as markers of erlotinib response in EGFR-wt patients. METHODS: F-18-FDG-PET/CT scans and blood samples were obtained prior to erlotinib initiation and were repeated after 1 week (PET/CT) and 1 to 4 weeks (blood sample) of treatment. Level of cfDNA was measured by droplet digital polymerase chain reaction. Percentage change (%∆) in SULpeak and total lesion glycolysis (TLG) on FDG-PET/CT and in plasma cfDNA was correlated to radiological response, progression-free survival (PFS), and overall survival (OS). RESULTS: Fifty patients were prospectively enrolled. A significant correlation was found between CT response and %∆TLG (P=.003). All patients with early metabolic progression showed radiological progression. Increased %∆TLG and %∆cfDNA were significantly correlated with shorter PFS (P=.002 and P=.004, respectively) and OS (P=.009 and P=.009, respectively). Multivariate analysis indicated %∆cfDNA to be the strongest predictor of OS. CONCLUSION: Early increase in TLG on F-18-FDG-PET/CT correlates with radiological progression, and shorter PFS and OS. Early increase in cfDNA predicts shorter PFS and OS. Both assessments are promising tools for early detection of nonresponders and reduced OS in TKI-treated EGFR-wt NSCLC patients.