Table 2.

Uncontrolled radiofrequency ablation studies

Ref.	Number of patients	Etiology	Type of study design	Case control analysis	Method	RFA device	Aim	Results
Steel et al[24]	22	CCC (n = 6) PC (n = 16)	Prospective	No	ERFA before SEMS	Habib EndoHPB	RFA catheter deployment, stent patency; adverse events (AE)	(1) 21/22 technical success; (2) 21/21 stent patency; 3/21 stent occlusion at 90 days; (3) AE 1 acute pancreatitis, 2 cholecystitis
Figueroa-Barojas et al[26]	20	CCC (n = 11) PC (n = 7) IPMN (n = 1) Gastric cancer (n = 1)	Prospective	No	ERFA before stenting (metallic or plastic)	Habib EndoHPB	Stricture diameter size; adverse events	(1) Significant increase of 3.5 mm duct diameter post RFA (P value < 0.0001); (2) 2 AE (1 mild pancreatitis, 1 cholecystitis)
Dolak et al[17]	58	MBO mainly CCC (n = 48)	Retrospective	No	ERFA + stenting, repeated ERFA for blocked SEMS, percutaneous RFA	Habib EndoHPB	Stent patency, survival adverse events, survival	(1) Median stent patency 170 d; Metal vs plastic stent (218 vs 115 d, P = 0.051); (2) Median survival 10.6 mo; (3) 12 AE (1 partial liver infarction, 5 Cholangitis, 2 hemobilia, 2 cholangiosepsis, 1 hepatic coma, 1 left bundle branch block)
Sharaiha et al[28]	69	CCC (n = 45) PC (n = 19) GB (n = 2) Gastric cancer (n = 1) Colon cancer liver metastasis (n = 3)	Retrospective (multicentric registry)	No	Mainly ERFA before placing metallic or plastic stent	Habib EndoHPB	Survival; stricture diameter; Adverse events	(1) Median survival 11.46 mo; (2) Significant improvement in stricture diameter post-ablation (P < 0.0001); (3) AE 10% (1 pancreatitis 2 cholecystitis, 1 hemobilia, 3 abdominal pain)
Laleman et al[25]	18	CCC, PC	Prospective	No	ERFA before stenting	ELRA	Feasibility, bilirubin level, survival and stent patency rate	(1) 6 AE (4 cholangitis, 2 pancreatitis); (2) Bilirubin level post-RFA decreased from 7.8 ± 1 mg/dL to 1.7 ± 0.4 mg/dL; P < 0.001; (3) Median survival of 227 d; (4) Stent patency 80% at 90 d and 69% at and 180 d respectively
Inoue et al[20]	41	MBO mainly CCC (n = 27) GB (n = 9)	Retrospective	No	ERFA before bilateral stenting (uncovered metallic)	Habib EndoHPB	Technical success; adverse effect; recurrent biliary obstruction (RBO) and stent patency rate	(1) Technical success was 95.1% (39/41); (2) 1 acute cholangitis, 1 cholecystitis, 1 nonocclusion cholangitis, 1 liver abcess; (3) RBO rate 38.5 % (15/39), and the median time to RBO was 230 d; (4) The median time to RBO was significantly longer in patients with strictures > 15 mm in length vs strictures ≤ 15 mm (314 vs 156 d; P = 0.02)

CCC: Cholangiocarcinoma; PC: Pancreatic cancer; GB: Gallbladder cancer; IPMN: Intradu ctal papillary mucinous neoplasm; RBO: Recurrent biliary obstruction.