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Yttrium-90 radioembolization (Y90) for treating primary liver cancers has evolved to include ablative dosing to small liver sectors (radiation segmentectomy (RS)) with unknown outcomes for RS in the setting of metastatic colorectal cancer (mCRC) to the liver. This study aimed to evaluate the safety and efficacy of RS for the treatment of mCRC. Withinstitutional review board approval, retrospective chart review included all patients with liver-dominant mCRC treated with RS (up to 2 Couinaud segments) from September 2009 to November 2019. Patient demographics, treatment details, CTCAE v5 adverse events, imaging response by RECIST, and overall survival (OS) were analyzed. Kaplan-Meier curves were generated from the date of RS and censored at last follow-up. Prognosticators for OS were examined by log-rank test and Cox proportional hazards regression. 45 patients met inclusion criteria (median age 61 years; 59% male); 37 (95%) had prior resection of primary site of disease. 49% had extrahepatic disease, 41% had prior liver resection, 24% had prior ablation, 77% had prior chemotherapy, and 59% were ECOG 0. The mean tumor size was 5.6 cm (range 1.2 to 13.5 cm). 70% of patients had liver tumor burden < 25%. Treatment was technically successful in all cases. 30-day mortality was 5%. Clinical adverse events were low-grade and included fatigue (G1 62%, G3 3%), abdominal pain (G1/2 24%), vomiting (G1/2 5%), and fever (G1 5%). The mean increase in neutrophil-to-lymphocyte ratio (NLR) was 3.2 (SD 5.2). Antitumor response included post-treatment decrease in CEA in 81%. The median number of imaging follow-ups was 3 (range 0 to 7). RECIST imaging response was PD 4%, SD 81%, PR 15%, CR 0%. The median OS after RS was 41.9 months (95% CI 15.4-44.4). Extrahepatic disease was a significant predictor of reduced OS (15.7 vs 43.1 months median OS, p=0.0043; HR 6.6, 95% 1.5 to 28.4, p0.011). Increased NLR was associated with worse OS HR 1.2 (95% 1.08-1.42, p=0.003). RS had an acceptable safety profile in heavily pretreated mCRC patients after systemic chemotherapy, locoregional therapy, and surgery. Extrahepatic disease and change in NLR were significant adverse prognosticators. Future investigation into the role of ablative Y90 in mCRC should be considered in select patients given promising OS outcomes.
Gordon et al. (Wed,) studied this question.