Cholangiocarcinoma (CCA) is an uncommon adenocarcinoma arising from the neoplastic transformation of cholangiocytes, the epithelial cells lining the intra-hepatic and extra-hepatic bile ducts. CCA accounts for about 3% of all digestive tumours and 10-15% of the hepatobiliary tumours. It has an annual incidence of 1-2 cases per 100,000 in the Western World, but rates of CCA have been steadily rising worldwide over the past several decades. On a global scale, CCA is the second most common primary hepatic malignancy These tumours have a poor overall survival with a 5-year survival of about 5%. Over 50% of patients present with advanced-stage disease, and the prognosis is poor with the survival of between 6-12 months for unresected patients, even after biliary decompression. CCA may arise anywhere in the biliary tree, from the small, peripheral hepatic ducts to the distal common bile duct. Commonly used classification systems utilise anatomical location to group tumours into three main categories: intra-hepatic (20-25%), perihilar (also including hilar/Klatskin tumour - 50%) and distal (20-25%).

Hilar CCA is an adenocarcinoma of the extrahepatic biliary tree arising from the main left or right hepatic ducts or their confluence. There has a been a growing recognition that hilar CCA disease actually has a distinct biological behaviour and natural history compared to that of (distal) extra-hepatic CCA, and increasing acknowledgment that different therapeutic strategies are required. At initial presentation of patients with extra-hepatic CCA, 30-50% will have local lymph node involvement and 10-20% metastatic spread typically to the liver and peritoneum. With hilar CCA due to the long asymptomatic course, only 20% are resectable at time of diagnosis.

Standard treatment options for CCA include surgery, radiotherapy and chemotherapy, dependent upon if the CCA is intra- or extra-hepatic. Tumour resection is the only potential cure for CCA. Recent advances in transplantation using stringent selection criteria and utilization of neoadjuvant chemoradiation have demonstrated encouraging results with 5 year survival rates of over 70%, with even one series from The Mayo Clinic yielding a 5-year survival rate of 82%. For the 80% who present with unresectable disease, the utility of these modalities combined with biliary decompression interventions only provided a median survival time of 3-6 months from the time of diagnosis.

For these patients with inoperable advanced CCA the main treatment aim is palliative to relieve local symptoms such as pain and jaundice. Surgery for these patients is primarily for creating a bypass in patients who cannot be stented. CCA is remarkably resistant to pharmacological therapy, but activity has been seen using chemotherapy; mainly gemcitabine given either as monotherapy or paired with either a platin derivative or a fluoropyrimidine as a doublet treatment and more recently docetaxel, these give partial response (PR) rates of 0-9% and an average survival advantage of 2-12 months. Concerning biological therapy, the ongoing studies using sorafenib, lapatinib or bevacizumab have yielded some promising results, with sorafenib demonstrating therapeutic benefit in a single arm Phase II study. For patients who are unsuitable for curative resection, the current systemic combination chemotherapy is with cisplatin plus gemcitabine. This was established in the largest randomized phase III study to date in non-operable biliary tract cancer which demonstrated a response rate of 81.4% and a median overall survival (OS) of 11.7 months; notably there was no statistically significant increase in toxicity when compared to gemcitabine monotherapy. The recent advances in interventional and endoscopic technology have seen a rise in highly specialized centres that are able to deliver very precise local control treatments aimed at gaining local control; these include local ablation and embolization, brachytherapy, radio-frequency ablation and, most significantly, photodynamic therapy which (PDT), with its favourable adverse-event profile, is recommended by most recent review articles for non-resectable patients.