Percutaneous Microwave Coagulation Therapy Using Cholangioscopy for Recanalizing Self‐expanding Metallic Stents Occluded by Tumor Ingrowth: Preliminary Results

Abstract

Abstract:Current ablative techniques for recanalizing self‐expanding metallic stents occluded by tumor ingrowth are limited by the risk of perforation or destruction of the stent filament. A previous experimental study revealed that microwave coagulation therapy for recanalizing occluded metal stents would be safe and effective, and we investigated the clinical application of this procedure. In this in vivo study, microwave coagulation therapy was performed for occluded metallic stents in 5 patients with pancreatic cancer and one patient with gallbladder cancer. This procedure was performed under percutaneous cholangioscopy and fluoroscopic control. Cumulative stent patency before and after microwave coagulation was estimated using the Kaplan‐Meier method supplemented with the log‐rank test. Tumor growing through the stent mesh was successfully removed without any complications using this technique. Analysis of stent patency did not reveal any significant difference between one session of coagulation therapy (115.0±18.4 days) and initial stent (102.3±.22.3 days). In contrast, none of the group after two sessions of this intervention was obstructed until their death. The results indicated that microwave coagulation therapy for recanalizing occluded metallic stent is effective and safe even in vivo. This procedure may be an alternative to placement of another stent through the occluded metallic stent. (Dig Endosc 1999; 11: 209–214)