CIO 2021-6 Radiation Segmentectomy for Oligometastatic Disease to the Liver: A Single Institution Experience

Purpose: To evaluate patient safety and treatment outcomes of radiation segmentectomy for metastatic disease to the liver.

Material and Methods: Retrospective review was performed for patients with malignancy metastatic to liver treated with radiation segmentectomy between 4/2018 and 7/2019. Clinical outcomes, imaging response, and laboratory values including pre- and 3-month post-procedural lab values were analyzed. 30-day post-procedural complications were evaluated using SIR Classification System for Complications by Outcome. Imaging outcomes were evaluated using mRECIST criteria.

Results: 7 patients with malignancy metastatic to liver (including oligometastatic or single dominant lesion: 3 colorectal, 2 neuroendocrine, 1 breast, 1 ovarian) unamenable to percutaneous ablation or surgical resection underwent 7 radiation segmentectomies using Yttrium-90 glass microspheres. All patients were non-cirrhotic with ECOG <2 and with localized hepatic disease affecting at most 2 liver segments. 2 patients had previous liver-directed therapy. Radiation segmentectomy was performed using a standardized protocol. The average treatment dose to target was >300 Gray (Gy). Patients were followed in outpatient clinic and all had follow-up imaging performed within 12 weeks of the procedure. 5 patients who have had at least 12-week imaging follow-up demonstrate mRECIST CR or PR in 100% of cases (3 CR, 2 PR). 2 patients who have had at least 10-month follow-up imaging demonstrate mRECIST CR in 100% of cases. Technical success was achieved in 100% of cases with no major complications reported within 30 days of the procedure. SIR Class A/B minor complications were reported in 6 of 7 cases including fatigue (4), nausea (2), and intractable abdominal pain (1). There were no significant changes from baseline in post treatment laboratory values.

Conclusions: Initial data suggests radiation segmentectomy may be a safe and effective treatment for metastatic disease to the liver in patients not amenable to surgical resection or percutaneous ablation. Further evaluation with larger cohort prospective data and with long-term results is required.