High dose rate intraluminal brachytherapy for unresectable bile duct cancer

In order to establish the protocol for high dose rate intraluminal brachytherapy with iridium in combination with external irradiation for unresectable bile duct cancer, the relationship between the dose of brachytherapy post external irradiation and its results and complication was studied and compared with that in other facilities. Subjects were 29 cases of the cancer receiving the above therapy. Two- or four- gated external irradiation was performed with 10 or 18 MV X-ray at 2 Gy/day with total dose of 40-50 Gy. Brachytherapy with percutaneous bile duct drainage was carried out twice at dose rates of 20 Gy/2 fx (9 cases), 25 Gy/5 fx (4) and 16 Gy/4 fx (16) and was evaluated by Radiation Therapy Oncology Group standard for the early response and by the standard of European Organization for Research and Treatment of duct Cancer for the late complication. Survival rate and statistical significance were evaluated by Kaplan-Meier and Cox-Mantel methods, respectively. Efficacy was evaluated by various imaging techniques. The recommended protocol was as follows: external irradiation 40 Gy x 20/4 weeks, then brachytherapy 16 Gy x 4/2 weeks and preventive brachytherapy around the fistulation 20 Gy x 2/2 weeks. Indwelling of the stent was also recommended when possible. (K.H.)