Safety and Effectiveness of Radiation Lobectomy for Primary Liver Cancers Using Resin Microspheres

To evaluate safety, hypertrophy, and kinetic growth rate (KGR) of future liver remnant following yttrium-90 radiation lobectomy (RL-⁹⁰Y) in liver cancer using resin microspheres.

This was a retrospective, single-center study. Patients with primary liver cancer who underwent RL-⁹⁰Y transarterial radioembolization (TARE) from November 2015 to December 2022 were reviewed. Twenty-eight patients (68% with HCC and 36% with iCCA) were included. The right lobe was treated in 18 of 28 patients (64%). Single-compartment dosimetry model was used. Total liver parenchymal volume (TLPV), treated parenchymal volume, and future liver remnant volume (FLRV) were recorded at baseline and after treatment at 0-4 months (T₁) and >4 months (T₂). Hypertrophy, FLRV/TLPV ratio, and KGR were calculated. Treatment response was categorized by modified Response Evaluation Criteria in Solid Tumors (RECIST) for hepatocellular carcinoma (HCC) and RECIST for intrahepatic cholangiocarcinoma (iCCA). Primary outcomes included safety profile, hypertrophy, and KGR. Secondary outcomes included disease response and proportion of patients bridged to surgery.

The hypertrophy and KGR at T₁ were 16% (interquartile range [IQR], 4%-28%) and 1.5% per week (IQR, 0.6%-2.3%) with increase in FLRV (P < .001) and FLRV/TLPV ratio (P < .001). KGR was higher at T₁ than at T₂ (1.3% vs 0.6%, P = .034). Treatment response (n = 27) was complete, partial, stable, and progressive in 53%, 24%, 6%, and 18% for HCC and 0%, 20%, 50%, and 30% for iCCA. Seven patients (25%) were bridged to resection at 2.5 months (IQR, 1.9-4.7 months). No differences were noted in atrophy, hypertrophy, and KGR at both time points (T₁ and T₂) when stratified on type of cancer, cirrhosis, portal vein thrombosis, or prescribed tumor dose.

RL-⁹⁰Y TARE using single-compartment dosimetry with resin microspheres can safely be performed in patients with primary liver cancer with KGR of 1.5% per week.