From June 2019 to December 2020 in each participating center, patients with recurrent rectal cancer after surgery and radiotherapy will be included in the study if they meet the inclusion criteria and do not meet the exclusion criteria. According to the clinical conditions of the patients, they will be assigned to groups A or B according to the doctor's recommendations and their own wishes. GTV of both groups are visible tumors. The CTV of group A is expanded by 3mm on the basis of GTV, and the CTV of group B is expanded by 6mm. Both groups A and B received prescription dose: 95% GTV (120-160) Gy, 95% CTV (90-120) Gy. The activities of 125I seeds will be 0.4mCi-0.7mCi. All patients will receive 3D printed template-assisted 125I seeds implantation and be followed up. The differences in local progression-free survival time, overall survival time, change of quality of life, and side effects between different groups will be prospectively analyzed.
This study is to explore the progression-free survival time (PFS) , overall survival time (OS), quality of life and side effects between two different clinical target volumes in the treatment of 3D printing template-assisted CT-guided radioactive iodine-125 seeds implantation for recurrent rectal cancer after surgery and radiotherapy and investigate the clinical and dosimetric prognosis factors for outcomes.