Frameless single-session robotic radiosurgery of liver metastases in colorectal cancer patients.

INTRODUCTION Due to advanced chemotherapy regimens, patients presenting with residual liver metastases of colorectal cancer (CRC) has increased. Surgery of residual metastases enhances overall survival, but surgical resection is often limited. Less invasive techniques have been invented to enhance local disease control. We investigated in a selected patient cohort local control of liver metastasis from CRC using robotic radiosurgery. METHODS AND MATERIALS In this study patients with colorectal liver metastases were prospectively followed after having been treated with single-session radiosurgery using a robotic image-guided device and real-time tumour tracking. The primary end-point was local control (LC); secondary end-points were toxicity, progression-free survival (PFS) and overall survival (OS). Extrahepatic metastases were excluded using a whole body (PET-CT: positron emission tomography computed tomography). Follow up was done by liver MRI every 3 months post-treatment. RESULTS Fourteen patients (median age 65 years), with a total of 19 colorectal liver metastases were treated with 24 Gy in one fraction. Median follow up was 16.8 months. A one-year LC rate of 87% and a median PFS of 9.2 months were reached. DISCUSSION Frameless robotic image-guided radiosurgery with real-time tumour tracking as an effective treatment for patients with colorectal liver metastases. This technique enhances the possibilities of multidisciplinary oncological concepts.