Neoadjuvant transarterial radiation lobectomy for colorectal hepatic metastases: a small cohort analysis on safety, efficacy, and radiopathologic correlation.

Colorectal cancer patients have a high incidence of liver metastasis (ml-CRC). Surgical resection is the gold standard for treatment of hepatic metastasis but only a small percent of patients are traditional candidates based on disease extent and adequate size of the future liver remnant (FLR). Interventions such as portal vein embolization (PVE) and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) are performed to increase FLR for operative conversion. Limitations to PVE include intrahepatic disease progression, portal vascular invasion, and utilization with concurrent chemotherapy. ALPPS is associated with a high morbidly and mortality. Radiation lobectomy (RL) with yttrium-90 (Y-90) delivers transarterial ablative brachytherapy to the future hepatectomy site which generates FLR hypertrophy similar or greater than PVE. Early results indicate that RL is safe, effective, and may offer unique benefits by providing cytoreduction of hepatic metastases which extends FLR hypertrophy time and allows FLR surveillance to gauge disease biology. A retrospective analysis of four patients with ml-CRC treated with RL prior to hepatectomy was performed to evaluate initial safety, efficacy, FLR hypertrophy, and radiopathologic correlation. Adverse events after RL and hepatectomy were evaluated. Imaging findings were analyzed for efficacy defined as FLR hypertrophy and disease control. Radiopathologic correlation was performed after histologic analysis. RL was well tolerated without major adverse events or hepatic decompensation. FLR hypertrophy ranged from 24.9% to 119% at mean follow-up of three months. The majority of complications were related to surgical instrumentation of the FLR due to upstaging at time of surgery. Hepatectomy specimen histology demonstrated complete pathologic response in 50% of patients, 50% radiopathologic concordance rate, and no significant hepatic fibrosis. Initial experience with neoadjuvant RL for ml-CRC is safe and provides both durable disease control and FLR hypertrophy with concurrent chemotherapy. A 50% complete pathologic response rate raises the possibility of definitive chemoradiation in poor surgical candidates. Prospective investigation is required.