Long-term Survival in Patients Treated with a Robotic Radiosurgical Device for Liver Metastases.

Purpose: The treatment of liver metastases with local procedures is a fast progressing field. For the most, long-term survival data is missing raising questions with regard to the efficacy of such modalities when compared to surgical resection. Radiosurgery using the CyberKnife device enables the treatment of liver lesions with a single-session approach. Here we present long-term survival data to explore the curative potential of this strategy.

Materials and Methods: Patients with oligo-metastatic disease limited to the liver have been treated with single-session or hypo-fractioned radiosurgery in curative intent and prospectively followed until death. Follow-up (FU) was performed using magnetic resonance imaging (MRI) two months after radiation and at 3-month intervals for the first 2 years. After that annual computed tomography or MRI scans were performed until 5 years post-treatment. Local recurrence in the radiated volume and recurrence outside the treated volume were used to define local and distant progression. Survival times were censored at the time of the last FU.

Results: One hundred twenty-six patients treated between 2005 and 2015 with 194 lesions were in-cluded into this study. Median FU was 30.0 months. According to Response Evaluation Crite-ria in Solid Tumors, 55.2% had a complete remission and 11.3% a partial remission. Seventy-two point two percent recurred outside the radiated lesion and median overall survival was 35.2 months with a 3-year survival rate of 47.7%.

Conclusion: This is currently the largest cohort of stereotactic body radiation therapy treated liver lesions with a median long-term follow of 30 months. Robotic radiosurgery using a single session approach has a high efficacy to control the radiated lesion with the potential to cure patients.