Robotic radiosurgery for the treatment of liver metastases.

Aim: This study evaluates the toxicity and outcome in patients treated with robotic radiosurgery for liver metastases.

Background: Modern technologies allow the delivery of high doses to the liver metastases while lowering the dose to the neighboring organs at risk. Whether this dosimetric advantage translates into clinical benefit is not well known yet.

Methods And Materials: A total of 9 patients with 17 liver metastases have been treated with robotic stereotactic body radiotherapy SBRT from March 2011 to December 2014. Local response to SBRT was graded by the Response Evaluation Criteria in Solid Tumors criteria to describe change in treated tumor lesion. Adverse events after SBRT were graded on a 1-5 scale according to the National Cancer Institute common terminology criteria for adverse events v4.0.

Results: Patients received either three (78%) or five (22%) fractions. Patients were treated with a mean fraction dose of 14 Gy with a range from 9 to 20 Gy. The median total radiation dose provided to patients was 45 Gy with a range of 45-60 Gy. Four out of the 17 (23.5%) treated lesions had a complete response, 9 (53%) partial response and 3 (17.6%) stable disease. With a median follow-up of 15.2 months after SBRT treatment, local control and overall survival rated were 89% and 66%, respectively. No patient experienced grade ≥3 toxicity. The most common toxicity reported was asthenia. Only two patients had nausea and diarrhea, 10 and 14 days after SBRT, respectively.

Conclusions: Robotic radiosurgery is a safe and effective local treatment option for secondary liver tumors. Further prospective studies are ongoing to determine long-term response and survival after robotic-SBRT for liver metastases.