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Chandrasekar et al. Mini-invasive Surg 2021;5:33 https://dx.doi.org/10.20517/2574-1225.2021.12 Page 11 of 16

[80]
relieving obstruction of the bile duct and tissue ingrowth in the SEMS . The technique involves advancing
the catheter over a guidewire towards the target site. There are two catheters primarily used for this
purpose: Habib Endo Bipolar Radiofrequency ablation catheter (Boston Scientific, USA) and Endoluminal
Radiofrequency Ablation (Taewoong Medical, South Korea). Case series have reported improved survival
and stent patency rates in patients who had RFA followed by SEMS in comparison to only SEMS. Increased
[81]
incidence of adverse events such as cholangitis, pancreatitis and cholecystitis have been noted . There is
currently a need for RCTs to demonstrate survival benefits with RFA.

Photodynamic therapy
PDT has been described as an endobiliary treatment for CCA, mainly hilar CCA. The treatment consists of
injection of a photosensitizing substance combined with irradiation of a laser at a specific wavelength .
[82]
This results in necrosis of the tumor cells by causing a disturbance in the vasculature and release of
[83]
cytotoxic enzymes from lysosomes causing degradation of cell membranes. Cheon et al. in their non-
randomized prospective study compared patients undergoing PDT and stenting with those undergoing only
biliary stenting for drainage. The median survival duration was longer in the PDT group compared to
stenting-only group (588 days vs. 288 days, P = 0.01) . There are published RCTs comparing PDT plus
[83]
stenting with biliary stenting only. Ortner et al. in their study on non-resectable CCA, demonstrated a
[84]
mortality benefit (median of 493 days vs. 98 days, P < 0.01) with improvement in quality of life. Zoepf
et al. in their RCT of 32 patients with bile duct cancer, demonstrated a longer duration of survival (21
[85]
months vs. 7 months, P = 0.01) in the PDT group, but there were also higher rates of post-intervention
cholangitis. Reports of bacterial cholangitis, liver abscesses and photo-toxicity to the skin ranging from 0%-
25% have been published in clinical studies. One major limitation of PDT is its availability, being restricted
only to large tertiary care centers, and phototoxicity to the skin and eyes. PDT has demonstrated good
efficacy by the destruction of superficial layers of the bile duct tumors up to 5 mm with significantly less
efficacy when tumor extension is beyond 7 to 9 mm depth . Currently, the indications for PDT are
[86]
sclerosing variant or superficial spreading type without mass variants of CCA without any distant or nodal
metastasis. Factors associated with the survival of patients have been studied for PDT. The presence of
lower serum albumin pre-treatment, visible mass on imaging and longer duration between diagnosis and
PDT treatment are associated with poorer survival rates while lower pre-treatment bilirubin level and
multiple PDT treatment sessions have demonstrated improved survival rates [87,88] .

EUS guided biliary drainage
When ERCP-guided biliary stenting failed, PTBD used to be the alternative treatment of choice. The
advancement in the field of interventional EUS has provided another approach for internal biliary drainage.
There are three different techniques for biliary drainage with EUS: (1) drainage of the intrahepatic ducts by
hepatico-gastrostomy (HGS); (2) drainage of the extrahepatic CBD by choledocho-duodenostomy (CDS);
and (3) EUS guided rendezvous procedure. In hepatico-gastrostomy, drainage is achieved by accessing a
dilated biliary radical mainly in the left hepatic duct system followed by dilation of the tract and placement
of a FCSEMS from the liver ducts to the gastric lumen . In CDS, access to the CBD is achieved from the
[89]
duodenal bulb followed by placement of a FCSEMS . Drainage can also be achieved by placement of a
[90]
[91]
metal stent in the gall bladder through the gastric antrum or duodenal bulb, if the cystic duct is patent .
The rendezvous procedure involves placement of a guidewire with the help of EUS guided access to the
CBD and through the papilla, and papillary cannulation achieved with the help of the duodenoscope over or
next to the guidewire. Both RCT data and meta-analyses have shown no difference in efficacy or safety
comparing HGS and CDS and the choice of approach should depend on the patient’s anatomy [92,93] . Recent
studies have shown EUS-BD to be a superior option when compared to PTBD with lower rates of
complications .
[94]