Clinical Efficacy of Stereotactic Radiotherapy and Microwave Ablation for Liver Metastases From Colorectal Cancer.

In the study，data of 100 colorectal cancer patients with liver metastases who received Cyberknife stereotactic radiotherapy or microwave ablation in the multi-center of the research group from June 2019 to May 2021 were collected, as well as follow-up data. 1. Radiation: Stereotactic Radiotherapy 1.1 Equipment: Accuray VSI Cyberknife stereotactic radiotherapy platform, simulated positioning CT machine, MR, positron emission computed tomography PET-CT, vacuum pad. 1.2 Radiotherapy localization: CT, MRI and PETCT were used to simulate localization. 1.3 Relevant Definitions of Tumor Targets CT, MRI, PET-CT fusion, combined with MRI location and PET-CT location image for sketching. To delineate target areas and organs at risk. GTV: Combining localization and fusion images to delineate the tumors seen PTV = GTV + 0-10mm Dangerous organs: The stomach, duodenum, jejunum, ileum, colon, spinal cord and esophagus were delineated on the base sequence of CT plain scan. The target area should be approved by at least one physician in charge or by a physician in charge. 1.4 Target volume radiation dose: According to the volume, location, organ function and other factors, the dosage of radiotherapy was determined. The range of BED value of radiotherapy was 90-120 when the distance between the tumor and gastrointestinal tract was more than 5 mm (alpha/beta=10) and 70-90 when the distance between the tumor and gastrointestinal tract was less than 5 mm (alpha/beta=10). 1.5 Normal Tissue Limit: Reference to TG101 Report 2. Microwave ablation 2.1 Preoperative positioning and planning: 2.1.1 Determine the fixing device: generally choose vacuum pad to fix 2.1.2 Choosing the right position: The principle is to choose the position that is easy to operate, taking into account the comfort and tolerance of patients. 2.1.3 CT scan 2.1.4 The range of tumors was determined by CT images. In principle, at the maximum level, the skin points corresponding to the vertical center of the tumor are the marker points of the locating needle. At the same time, the center of the tumor was taken as the origin point, and the longitudinal and transverse cross lines were drawn on the patient's body surface. Roughly delineate the range of tumors according to CT in body surface 2.2 Surgery and intraoperative optimization 2.2.1 Posture reduction and fixation of patients 2.2.2 Oxygen inhalation, ECG and blood pressure monitoring 2.2.3 Installation of 3D Printing Planar Coordinate Template Fixer 2.2.4 Routine disinfection, cave towel laying, local infiltration anesthesia, fixing 3D printing plane coordinate template according to the range of tumors determined by physical examination and preoperative plan, and adjusting the direction of plane template by protractor. 2.2.5 Puncture locating needle and puncture assistant fixing needle in 4 directions of tumor margin. 2.2.6The real-time CT 2.5mm image was imported into the navigation system, the puncture needle was marked, the puncture needle was simulated, and the resolution of the template was adjusted accurately. 2.2.7 Enhanced CT scan to determine the position and angle of template and pin accurately 2.2.8 Layer by layer puncture according to preoperative plan 2.2.9 After inserting the ablation antenna to the reserved position, scan CT again to confirm whether the puncture needle has reached the planned position. 2.2.10 Complete ablation of tumors as planned. 2.3Postoperative observation 2.3.1 With the assistance of the staff in the hospital, they will be transported back to the ward by flat car with their families. 2.3.2 Re-measurement of blood pressure and heart rate 2.3.3Observe whether there is bleeding or exudation at the puncture point after operation, and give hemostasis and pain relief if necessary. To evaluate the clinical efficacy of stereotactic radiotherapy and microwave ablation in liver metastases after these treatment.In addition, the local control rate and side effects of stereotactic radiotherapy and microwave ablation in the treatment of liver metastases were explored, and the efficacy and safety of different doses of stereotactic radiotherapy were determined.