Background and aim: Covered self-expandable metal stents (EMS) were recently developed to overcome tumour ingrowth in conventional EMS. However, supporting evidence for the efficacy of covered EMS is lacking. Patients and methods: We enrolled 112 patients with unresectable distal biliary malignancies. They were randomly assigned to polyurethane covered (n = 57) or original diamond stent (n = 55). Results: Stent occlusion occurred in eight patients (14%) after a mean of 304 days in the covered group, and in 21 patients (38%) after a mean of 166 days in the uncovered group. The incidence of covered EMS occlusion was significantly lower than that of uncovered EMS (p = 0.0032). The cumulative stent patency of covered stents was significantly higher than that of uncovered stents (p = 0.0066). No tumour ingrowth occurred in the covered group while it was observed in 15 patients in the uncovered group. In subgroup analysis, the cumulative patency of the covered EMS was significantly higher in pancreatic cancer (p = 0.0363) and metastatic lymph nodes (p = 0.0354). There was no significant difference in survival between the two groups. Acute cholecystitis was observed in two of the covered group and in none of the uncovered group. Mild pancreatitis occurred in five of the covered group and in one of the uncovered group. Conclusions: Covered diamond stents successfully prevented tumour ingrowth and were significantly superior to uncovered stents for the treatment of patients with distal malignant biliary obstruction. However, careful attention must be paid to complications specific to covered self-expandable metal stents, such as acute cholecystitis and pancreatitis.
Histopathologic examination was done on 18 cases after percutaneous ethanol injection therapy (PEIT) for hepatocellular carcinoma. In eight cases, the lesion was treated by PEIT alone; in the other ten cases, PEIT was combined with transcatheter arterial embolization. The lesion was completely necrotic in 13 cases, 90% necrotic in four cases, and 70% necrotic in the rest. In addition, PEIT seemed to be effective against intercapsular, extracapsular, and vascular invasions. In the four cases of incomplete necrosis, the viable cancer tissue remained in small tumor nodules around the main tumor, in portions isolated by septa, or along the edge of the lesion. Therefore, ethanol should be injected not only into the center of the lesion, but also into sites close to its edge. Ethanol did not damage noncancerous liver parenchyma distant from injected sites. Local dissemination of the cancer cells was not found in any case. Therefore, PEIT seems to be a valuable therapy and may be an alternative to surgery in some cases.
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