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99m Tc-EDDA/HYNIC-TOC is an easily available and cheaper radionuclide that could be used for somatostatin-receptor-based imaging of neuroendocrine tumours (NETs). We aimed to evaluate the diagnostic performance of 99m Tc-EDDA/HYNIC-TOC compared to 111 In-DTPA-octreotide in patients (pts) with NETs. We performed a prospective diagnostic study including pts with biopsy-confirmed NET and at least one visible lesion at conventional imaging. Two independent nuclear medicine physicians evaluated pts who underwent 99m Tc and 111 In scans and images. The primary outcome was comparative diagnostic accuracy of 99m Tc and 111 In. Secondary outcomes include safety. Nine pts were included and performed 14 paired scans. Overall, 126 lesions were identified. 99m Tc demonstrated superior sensitivity both when all images were analysed (93.7, 95% CI 88.1% - 96.8% versus 74.8%, 95% CI 66.6 - 81.6%, p < 0.001) and when liver-specific images were analysed (97.8%, 95% CI 92.7% - 99.5% versus 85.1%, 95% CI 76.6% - 91.0%, p < 0.001). 99m Tc was also associated with a lower negative likelihood ratio (LR) (0.002, 95% CI 0.009 - 0.1 versus 0.19, 95% CI 0.12 - 0.42, p = 0.009) when evaluating hepatic lesions. Adverse events happened in 3 pts after 111 In and in 2 pts after 99m Tc, all grade 1. The 99m Tc demonstrated a higher sensitivity overall and a better negative LR in liver-specific images compared to 111 In in pts with NETs. Our findings suggest that 99m Tc is an alternative to 111 In and is especially useful in ruling out liver metastases. NCT02691078., Competing Interests: Dr Moriguchi-Jeckel and Dr Werutsky report grants from Financiadora de Estudos e Projetos (FINEP) for the conduct of the study. Drs R. Madke, Viana, Nabinger, and Fernandes report employment relationships with the RPH Group. Dr. Werutsky reports personal fees from AstraZeneca, Bayer, Beigene, Daiichi Sankyo, Genentech/Roche, GSK, Lilly, MSD, Novartis, Pfizer, Sanofi, and Seattle Genetics outside the submitted work. The other authors declare that they have no conflict of interest., (© the authors; licensee ecancermedicalscience.)

Background: The present study aims to assess the performance of 18F-FDG PET-CT on mediastinal staging of non-small cell lung cancer (NSCLC) in a location with endemic granulomatous infectious disease., Methods: Diagnostic test study including patients aged 18 years or older with operable stage I-III NSCLC and indication for a mediastinal lymph node biopsy. All patients underwent a 18F-FDG PET-scan before invasive mediastinal staging, either through mediastinoscopy or thoracotomy, which was considered the gold-standard. Surgeons and pathologists were blinded for scan results. Primary endpoint was to evaluate sensitivity, specificity and positive and negative predictive values of PET-CT with images acquired in the 1st hour of the exam protocol, using predefined cutoffs of maximal SUV, on per-patient basis., Results: Overall, 85 patients with operable NSCLC underwent PET-CT scan followed by invasive mediastinal staging. Mean age was 65 years, 49 patients were male and 68 were white. One patient presented with active tuberculosis and none had HIV infection. Using any SUV&#95;max > 0 as qualitative criteria for positivity, sensitivity and specificity were 0.87 and 0.45, respectively. Nevertheless, even when the highest SUV cut-off was used (SUV&#95;max ≥5), specificity remained low (0.79), with an estimated positive predictive value of 54%., Conclusions: Our findings are in line with the most recent publications and guidelines, which recommend that PET-CT must not be solely used as a tool to mediastinal staging, even in a region with high burden of tuberculosis., Trial Registration: The LACOG 0114 study was registered at ClinicalTrials.gov , before study initiation, under identifier NCT02664792.