A Primary Liver Cancer Patient Treated With Stereotactic Body Radiation Therapy Using Diaphragm Motion Surrogate Tracking in CyberKnife.

Stereotactic body radiotherapy (SBRT) is one of the safe and effective treatment options for primary liver cancer. This case report describes a 64-year-old patient diagnosed with primary liver cancer after a contrast-enhanced T1-weighted MRI scan, which revealed a 4.4×5.0 cm mass in the upper segment of the right anterior lobe of the liver. The patient underwent SBRT using diaphragm motion surrogate tracking (DMST) with a dose of 45 Gy delivered in six fractions to the lesion, followed by oral Sorafenib and regular imaging follow-ups. Post-treatment MRI showed that the tumor had shrunk to 0.8cm. This case highlights the efficacy of CyberKnife SBRT in managing liver tumors near the diaphragm dome, achieving a radiographic response. CyberKnife SBRT delivers high-dose radiation to tumors while sparing surrounding normal tissues through high-precision radiotherapy and tracking technologies, particularly suitable for respiratory motion-related lesions. In this case, the patient had a local progression at 23 months and died at 46 months after SBRT. This preliminarily shows the feasibility of integrating DMST into the respiratory motion model for CyberKnife SBRT in treating liver tumors adherent to the diaphragm dome.