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Abstract Background Mesenchymal-epithelial transition exon14 (METex14) skipping is one of the therapeutic driver oncogene mutations in non-small cell lung cancer (NSCLC), and can be treated with tepotinib and capmatinib. There is only one report on computed tomography (CT) findings of METex14 skipping-positive NSCLC, which shows that the primary tumor tends to have a large mass in the upper lobe, and extrathoracic metastases are common. This study examined the CT findings of METex14 skipping-positive NSCLC, focusing on the features of the margins and internal structures. Methods We consecutively included patients with METex14 skipping-positive NSCLC who were diagnosed between January 2018 and December 2020 at four independent institutions. We retrospectively reviewed the patient demographics and CT findings for tumor margins (invasion into surrounding tissue, lobulation, pleural indentation, spicula, and ground-glass opacity) and internal structures (air bronchograms, cavitation and internal low-density area). Results Fifteen patients with METex14 skipping-positive NSCLC were identified. Almost half of the patients were men (7/15; 46.7%), and their median age was 75.0 years. More than half were either current or former smokers (9/15; 60.0%). A vast majority of histological subtypes were adenocarcinoma (10/15; 66.7%), followed by pleomorphic carcinoma (3/15; 20.0%) and squamous cell carcinoma (2/15; 13.3%). With regard to CT findings, most primary tumors presented as masses larger than 30 mm (12/15; 80.0%) and were located in the upper lobes (12/15; 80.0%). Invasion into surrounding tissue and presence of internal low-density areas were observed in 60.0% (9/15) and 66.7% (10/15) of the primary tumors, respectively. Additionally, their frequencies increased to 72.7% (8/11) and 90.9% (10/11) in stage III/IV cases, respectively. In lymph node metastasis, internal low-density areas were observed in 8/10 cases (80.0%). Although these two CT features were rarely observed in distant metastases at diagnosis, they became apparent with progression of the metastatic tumor size. Conclusions METex14 skipping-positive NSCLC tumors tend to invade surrounding tissue and possess internal low-density areas. These CT findings might be characteristic of METex14 skipping-positive NSCLC.

Abstract The IMpower133 regimen, composed of atezolizumab/etoposide (VP‐16)/carboplatin (CBDCA), is the standard first‐line treatment for extensive‐stage small cell lung cancer (ES‐SCLC). However, the safety and efficacy of triplet therapy in patients receiving dialysis have not been sufficiently evaluated. Here, we report two cases of dialysis patients with ES‐SCLC who received the modified IMpower133 regimen. Patient 1 was a 69‐year‐old man, and patient 2 was a 73‐year‐old man who received dialysis because of end‐stage renal failure caused by diabetic nephropathy. Both patients received a modified IMpower133 regimen in the following order: atezolizumab (1200 mg/body) on day 1, VP‐16 (50 mg/m2) on days 1 and 3, and CBDCA (300 mg/m2) on day 1. Four hours of dialysis was performed 1 hour after completing the administration of CBDCA on Day 1 and 2 hours after completing the administration of VP‐16 on Day 3. Both patients achieved a partial response and received atezolizumab maintenance therapy after four cycles of triplet therapy without uncontrollable adverse events. By modifying the dosage, the order of drugs, and the timing of dialysis, the IMpower133 regimen may be tolerable and effective for patients receiving dialysis.