2 The procedure
2.1.1 Bile duct cancer may prevent bile flowing from the liver to the intestine. Early cancers are often asymptomatic, but as the disease advances patients may experience symptoms from biliary obstruction, such as jaundice, itchy skin, abdominal discomfort, loss of appetite, loss of weight and fever. PDT is a palliative treatment option for bile duct cancer.
2.1.2 Treatment options depend on the stage, size, position and type of tumour. Bile duct cancer is not usually diagnosed before the symptoms of biliary obstruction occur, by which time the cancer may be too advanced for curative surgical resection. Options for palliative treatment include surgical bypass of the bile duct or the insertion of a stent using surgical, endoscopic or percutaneous techniques. The benefits of other palliative treatments such as radiotherapy, chemotherapy and brachytherapy are still being investigated.
2.2.1 PDT produces localised tissue necrosis. A photosensitising agent is applied that is absorbed into the tumour tissue. The area is then exposed to laser light of an appropriate wavelength.
2.2.2 PDT is usually administered in conjunction with a biliary stenting procedure. The photosensitising agent is injected intravenously and photoactivation is performed approximately 48 hours later. A laser is inserted through a translucent endoscopic catheter situated close to the tumour, or it is placed directly across the tumour. Radiological control is used to ensure correct positioning of the laser fibre. Patients remain in subdued lighting for about 3 days after injection to avoid skin photosensitivity and are then gradually readapted to light. The treatment can be repeated.
2.3.1 A randomised controlled study of 39 patients reported that those treated with PDT and biliary stenting had a significantly longer median survival time than patients treated with biliary stenting alone (493 days versus 98 days, p < 0.0001). This study was terminated prematurely because PDT was so superior to stenting alone. Several quality-of-life scores were significantly improved after PDT, including global quality of life, fatigue, itching and weight loss. No significant improvements in quality-of-life scores were reported for the patients receiving biliary stenting alone. A non-randomised study of 44 patients reported that the mean survival after PDT and biliary stenting was 16 months, compared with 12.5 months after biliary stenting alone. For more details, refer to the Sources of evidence.
2.3.2 The Specialist Advisors considered that there is not yet enough data to draw clear conclusions about the effect of PDT on survival. One Specialist Advisor stated that this procedure is only effective for tumours that are in visual proximity to the light source.
2.4.1 The most common complications were cholangitis, affecting between 15% (3/20) and 56% (13/23) of patients, and photosensitivity, which was reported in 0% (0/8) to 33% (2/6) of patients. Other reported complications included bilioma, cholecystitis, stenosis and haemobilia. For more details, refer to the Sources of evidence.
2.4.2 The Specialist Advisors stated that potential adverse effects of the procedure include cholangitis, photosensitivity, stenosis of the biliary tree, biliary perforation, acute pancreatitis, bleeding and pain.