Cholangiocarcinoma

While cholangiocarcinoma (CC) is still a rare tumor, a strong increase in its incidence especially in Western countries for reasons which are largely unknown can be observed. Unfortunately, patients are often diagnosed late and frequently when the tumor has already metastasized. In rare tumors like CC, it is therefore especially important to identify risk factors as this might help to develop surveillance programs for high-risk patients. New risk factors for CC have emerged, including obesity which is a known risk factor for hepatocellular carcinoma (HCC). Other risk factors such as primary sclerosing cholangitis have been known for a long time, and the pathomechanisms which connect chronic inflammation with tumor development in the biliary system are further emerging.

CC is difficult to diagnose even if suspected, and the sensitivities and specificities of the different imaging modalities, ranging from computed tomography to magnetic resonance imaging and ultrasound, for the different subtypes of CC need to be observed in order to choose the right modality. Not only improved image acquisition and processing but also the use of new contrast agents or the combination of different modalities might help us to further improve the radiological diagnosis of these tumors.

Endoscopy and specifically endoscopic retrograde cholangiopancreatography and endoscopic ultrasound are needed for the diagnosis and treatment of CC. Endoscopic diagnosis of CC therefore remains a suitable option for many patients when it is integrated into a comprehensive diagnostic workup. New endoscopic treatments like radiofrequency ablation are being developed; however, the available data is still sparse and has not been systematically compared to other treatment options yet. The same holds true for locoregional treatment of this disease which has seen a flurry of new studies being published in recent years. Given the rarity of the tumor and the differences in the way the treatments were performed, it is currently difficult to draw clear conclusions from this. Nevertheless, these treatments will become part of multidisciplinary therapy in the future. Surgical resection, performed at expert centers using the proper technique, remains the only curative option at the moment. Tremendous progress has been made in recent years, and the improvement of surgical technique led to meaningful advances in the field. One of the areas which have sparked interest after years of disappointment is liver transplantation for cholangiocarcinoma. Liver transplantation was tested many decades ago but was deemed unsuitable until recently when new integrated concepts of neoadjuvant treatments emerged which might make this treatment option available for highly selected patients.

Which therapy is right for which individual patient remains a difficult question to answer and usually requires the patient to be referred to a center which treats patients with CC regularly. Maybe the advancement of molecular diagnostics will help us with this decision in the future as the first data is available on molecular aberrations and aids in the stratification of these patients. It might also help in the development of better systemic treatments as we begin to understand the molecular underpinnings of this disease in greater detail and the exiting new prospects of immuno-oncology enter this area of oncology.

The field of CC research is advancing rapidly at the moment and we will also need to use this knowledge to derive treatment guidelines in the future. CC, like HCC, is a tumor that can only be treated when different disciplines of medicine work together closely as combined diagnostic and therapeutic approaches are of utmost importance.

For this issue of Visceral Medicine we asked a number of experts in the field of diagnostics and therapy to summarize the most recent findings in their respective areas. We hope that this might help our colleagues to identify and treat this difficult disease.