Radiographical Evaluation of Tumor Immunosuppressive Microenvironment and Treatment Outcomes in Gastric Cancer: A Retrospective, Multicohort Study.

BACKGROUND: The tumor immunosuppressive microenvironment can influence treatment response and outcomes. A previously validated immunosuppression scoring system (ISS) assesses multiple immune checkpoints in gastric cancer (GC) using tissue-based assays. We aimed to develop a radiological signature for non-invasive assessment of ISS and treatment outcomes. METHODS: A total of 642 patients with resectable GC from three centers were divided into four cohorts. Radiomic features were extracted from portal venous-phase CT images of GC. A radiomic signature for predicting ISS (RISS) was constructed using the least absolute shrinkage and selection operator (LASSO) regression method. Moreover, we investigated the value of the RISS in predicting survival and chemotherapy response. RESULTS: The RISS, which consisted of 10 selected features, showed good discrimination of immunosuppressive status in three independent cohorts (area under the curve = 0.840, 0.809, and 0.843, respectively). Multivariate analysis revealed that the RISS was an independent prognostic factor for both disease-free survival (DFS) and overall survival (OS) in all cohorts (all p < 0.05). Further analysis revealed that stage II and III GC patients with low RISS exhibited a favorable response to adjuvant chemotherapy (OS: hazard ratio [HR] 0.407, 95% confidence interval [CI] 0.284-0.584); DFS: HR 0.395, 95% CI 0.275-0.568). Furthermore, the RISS could predict prognosis and select stage II and III GC patients who could benefit from adjuvant chemotherapy independent of microsatellite instability status and Epstein-Barr virus status. CONCLUSION: The new, non-invasive radiomic signature could effectively predict the immunosuppressive status and prognosis of GC. Moreover, the RISS could help identify stage II and III GC patients most likely to benefit from adjuvant chemotherapy and avoid overtreatment.

[Value of computed tomography and magnetic resonance imaging in diagnosis and differential diagnosis of small hepatocellular carcinoma].

OBJECTIVE: To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of small hepatocellular carcinoma to improve the accuracy in the diagnosis. METHODS: This retrospective analysis involved 41 patients with small hepatocellular carcinoma cases confirmed by pathological examination of the biopsy samples or follow-up. These patients were assessed for CT and MRI findings including lesion size, density or signal intensity, enhancement patterns, and presence of tumor capsules. RESULTS: On unenhanced CT images, small hepatocellular carcinomas were displayed mainly as low-density masses, and the majority of tumors presented with low signal intensity on T1-weighted unenhanced MR images with increased signal intensity on T2-weighted images in comparison with the surrounding liver parenchyma. Most of tumors showed intense enhancement during the arterial phase (CT in 15 cases and MRI in 13 cases), but some appeared isointense to the liver parenchyma (CT in 4 cases and MRI in 4 cases). In portal and delayed phases, the tumors typically had lower signal intensity than that of the surrounding liver tissues (CT in 25 cases and MRI in 12 cases) with enhancement of the tumor capsules (13 cases). CONCLUSION: Dynamic enhanced scanning can be more informative of the pathology and blood supply of small hepatocellular carcinoma. Early and late arterial phase imaging may help in detecting the small lesions and in making differential diagnosis.