Comparison of endoscopic radiofrequency ablation combined with biliary stenting versus stenting alone for the treatment of unresectable malignant biliary obstruction : Prospective randomized controlled pilot study

This study started patient registration in July 2020, registering a total of 11 people (5 in the RFA+stent group and 6 in the Stent-only group), and then the originally planned 12th subject registration was delayed, and therefore the clinical trial ended with 11 people registration in December 2021, and the survival period was tracked until October 1, 2022. There were no differences in gender ratio, age, BMI, Karnofsky performance scale, and causative diseases between the two groups. There was no statistical difference in tumor location between the two groups, but there were two Hilar lesions, three Extrahepatic lesions in the RFA+stent group, and only six Extrahepatic lesions in the Stent-only group. Although there was no statistical difference between the two groups in the AJCC staging, there were 1 stage III, 4 stage IV in the RFA+stent group, 1 stage I, 2 stage II, and 3 stage IV in the Stent-only group (Table 1). The stent patency period for the primary purpose of the study was longer in the Stent-only group than in the RFA+stent group (mean stent patency 54.2 ± 17.2 vs 320.7 ± 89.7 days, P = 0.007) (Figure 1). The survival rate for the secondary purpose of the study was also longer in the Stent-only group compared to the RFA+stent group (median survival 107.0 ± 35.1 vs 194.0 ± 84.5 days, P = 0.003). (Fig 2). Many other previous studies examining the effectiveness of RFA used metal stent in both the RFA+stent and Stent-only groups. In this pilot study, we used plastic stents in the RFA+stent group and metal stents in the Stent-only group to easily remove previously inserted stents in the RFA group, which may require multiple re-procedures, and to facilitate RFA procedures during re-procedures. However, the number of patients was too small due to the pilot study and it is thought that the results were affected by the fact that stage III and IV, which are the progress of the disease, had most of the patients in the RFA+stent group and Hilar lesions was only in the RFA+stent group although there were no statistically different Therefore, in the future, it is thought that pilot or multi-center studies will be needed to limit the location of the tumor to Hilar or Extrahepatic lesion and have the degree of disease progression similar between two groups.