Bile duct cancer or cholangiocarcinoma is the cancer affecting the slender tubes that carry the digestive bile fluid. The liver is connected to the small intestine and the gallbladder by the bile duct. Cholangiocarcinoma is rare and can develop in people at any age, but it generally occurs in those aged above 50 years.
Comparatively, the study of bile duct cancer is difficult. Around the world, research on the cause, diagnosis, and treatment of bile duct cancer is ongoing at many medical centers.
Research on bile duct surgery
To treat bile duct cancer, doctors are continually trying to improve ways to bring more people to the surgical table. Liver transplantation is considered to be the best choice of treatment for bile duct cancer but other choices are also being analyzed. For instance, technical removal of cancer in the liver by surgery can be done, but this may lead to not much healthy liver left after surgery.
Portal vein embolization is a method used to block the transportation of blood to one part of the liver. As this particular portion of the liver is compressed, the remainder of the liver expands to compensate for this. After a few weeks, the expanded side of the liver gets healthier, and thus ensures the possibility of the tumor on the other side to be removed by performing an operation.
Liver transplantation and its research
In the USA, research on liver transplants is being doneon people for whom the intrahepatic and hilar bile duct cancers remain without spreading. However, when both lobes of the liver are affected, removal of tumor is not possible with surgery. In this condition, the surgeon cannot recommend a transplant. For many people transplant is not a choice, as finding a liver donor is extremely difficult.
There is always a danger of the cancer to recur in transplant surgery. People who have undergone surgery are likely to survive for 5 years in the ratio of 1:5.
However, recent research results also state that the danger of acquiring cancer again is lowered by undergoing chemoradiotherapy (combination of radiotherapy and chemotherapy) before surgery. Almost 50% of such liver transplant patients live for 5 years or more after completion of surgery. It has also been seen that 4 of 5 patients survived for 5 years after undergoing chemoradiotherapy prior to surgery. Severe side effects are caused due to this treatment, which is available only for a small group of people who have cancer at an early stage that is not spread.
Therapies related to research on bile duct cancer
1. Chemotherapy and radiation therapy
To boost the performance of radiation therapy, researchers are evaluating different techniques. Three-dimensional conformal radiation therapy (3D-CRT), stereotactic body radiation therapy (SBRT), and intensity modulated radiation therapy (IMRT) are techniques that are widely used by doctors because theyare directed at only the tumor cells and not normal tissue. Intraoperative radiation (IORT) and proton beam radiation therapy techniques can be used but are mostly unavailable.
For bile duct cancer, a mixture of new drugs is being tested as the effect of chemotherapy is not adequate. Studies are undergoing for giving chemo in different ways. For example, the combination of chemotherapy and embolization called trans-arterial chemoembolization (TACE). Chemo drugs are often given in the form of tiny beads to stop and fill the hepatic artery.
2. Light therapy
Here, photodynamic therapy (PDT) is used to destroy cancer cells using light. First, a drug that is sensitive to light and acceptable by the cancer cell is consumed. Then bright light is shone on the cancer cell, which destroys the cancer cells by stimulating the drug. Second, to clear blocks and initiate smooth flow from bile duct to bowel, a small stent (a tiny tube) is placed in the bile duct. A few problems come up while doing this trial.
During this trial the stent, which is sent to the bile duct, works efficiently along with PDT, and more so than with only the stent.
- The efficiency of having a stent is not known in its early stage.
- In previous results, they were unaware of the fact that having only a stent is not enough.
This trial has closed and the results are awaited.
The drug administered with PDT is thought to be destroyed by the body. Conversely, doctors also think that actually a small portion of the drug remains in the body even a month after treatment, which keeps growing and shows up during further treatment. Phase 4 of the research is investigating the duration of the stay of the drug in the body, and the possibilities of side effects during a second dose.
3. Radiofrequency ablation (RFA)
Cancer cells are destroyed by heat produced by radio waves. Radiofrequency is one form of electrical energy used in ablation. Research says that bile duct cancer that cannot be removed from the liver by surgery can be controlled by RFA. Some researchers declare that bile duct cancer that comes after surgery in the liver can also be controlled.
Reviewed by Afsaneh Khetrapal BSc (Hons)