The purpose of
radiation therapy for unresectable
biliary tract cancer is to prolong survival or prolong
stent patency, and to provide palliation of
pain. For unresectable
bile duct cancer, there are a number of studies showing that
radiation therapy is superior to the best supportive care. Although
radiation therapy is used in many institutions, no large randomized controlled trials (RCTs) have been performed to date and the evidence level supporting the superiority of this treatment is low. Because long-term relief of
jaundice is difficult without using biliary stenting, a combination of
radiation therapy and
stent placement is commonly used. As
radiation therapy, external-beam
radiation therapy is usually performed, but combined use of intraluminal
brachytherapy with external beam
radiation therapy is more useful for making the treatment more effective. There are many reports demonstrating improved response rates as well as extended survival and time to recurrence achieved by this combination
therapy. Despite the low level of the evidence, this combination
therapy is performed at many institutions. It is expected that multi-institutional RCTs will be carried out. Unresectable
gallbladder cancer with a large focus is usually extensive, and normal organs with high radio sensitivity exist contiguously with it. Therefore, only limited anticancer effects are to be expected from external beam
radiation therapy for this type of
cancer. The number of reports on ampullary
cancer is small and the role of
radiation therapy in this
cancer has not been established. Combination treatment for ampullary
cancer consists of either a single use of intraoperative
radiation therapy, postoperative external beam
radiation therapy or intraluminal
brachytherapy, or a combination of two or three of these
therapies. Intraoperative
radiation therapy is superior in that it enables precise irradiation to the target site, thereby protecting adjacent highly radiosensitive normal tissues from irradiation. There are reports showing extended survival, although not significant, in groups undergoing intraoperative or postoperative
radiation therapy compared with groups without
radiation therapy. To date, there are no reports of large RCTs focusing on the significance of
radiation therapy as a postoperative adjuvant treatment, so its usefulness as a postoperative adjuvant treatment is not proven. An alternative treatment is
photodynamic therapy. There is an RCT demonstrating that, in unresectable
bile duct cancer, extended survival and improved quality of life (QOL) have been achieved through a combination of
photodynamic therapy and biliary stenting, compared with biliary stenting alone. Results from large RCTs are desired.