Each patient undergoes a detailed educational process on PDT after which informed consent is obtained. Patients treated with PDT receive Porfimer sodium (Photofrin; Axcan Pharma Inc.) at a dosage of 2 mg/kg body weight intravenously 48 hours before laser activation.
Endoscopic retrograde cholangiography (ERC) is performed using a large channel duodenoscope (TJF-140, TJF-160, and TJF-160VF; Olympus America, Center Valley, PA, USA). After cannulation into the biliary tract, a cholangiogram is performed to help define the anatomic distribution of malignant tissue and the extent of disease within the biliary ducts. Careful opacification of the dilated segments is performed selectively. Next, selective bougie and balloon dilation of the stricture(s) to be treated is performed to facilitate diffuser placement within the malignant stricture.
Photodynamic therapy is delivered through a 3.0-m length fiber with a 2.5-cm-long cylindrical diffuser at its distal end (Pioneer Optics, Windsor Locks, CT, USA). The diffuser can be inserted into a 10 F sheath of a plastic stent delivery system and placed at the level of the stricture being treated.37
Alternatively, our group has been using the single operator cholangioscopy (SOC) as a platform to administer PDT (Spyglass; Boston Scientific, Natick, MA, USA).40
A diode laser system (InGaAIP Laser Diode; Diomed Inc., Andover, MA, USA) with a maximum power output of 2,000 mW and a wavelength of 633±3 nm is used as a light source.
Photoactivation is performed at 630 nm with a light dose of 180 J/cm2
, fluence of 0.250 W/cm2
and irradiation time of 750 seconds. Multiple segments can be treated at the discretion of the endoscopist. When tumor length exceeds the maximal diffuser length, overlap of treated areas should be avoided by a stepwise pull-back of the fiber under fluoroscopic guidance. Placement of endoprostheses is performed systematically after the photodynamic treatment to prevent cholangitis.37
PDT is typically repeated at 3-month intervals at which time all stents should be replaced; stents are exchanged earlier in the case of premature occlusion or migration to maintain optimal decompression. All patients should receive peri-operative antibiotic prophylaxis. Post-operatively, patients treated with PDT are advised to remain out of direct sunlight since Porfimer sodium may cause prolonged photosensitivity lasting 30-90 days.41