Abstract No. 268 Modified Radiation Lobectomy as Bridge to Liver Resection: A Single-Center Experience

To investigate outcomes of patients who received modified radiation lobectomy for hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). Institutional review board approved this retrospective study of patients who underwent modified radiation lobectomy with yttrium-90 (90Y) glass microspheres for HCC or ICC with intent to grow the future liver remanent (FLR) between 2019-2022. Outcome measures included tumor response according to modified Response Evaluation Criteria in Solid Tumors (mRECIST), FLR kinetics, tumor progression, and surgical resection or liver transplantation. Adverse events were assessed according to the Society of Interventional Radiology classification. Descriptive statistics were used to assess data. Fifteen patients (7 women, 8 men; mean age 66 ± 11 years) with HCC (n = 7) and ICC (n = 8) underwent modified radiation lobectomy of left (n = 1) or right (n = 14) sided tumors. Mean index tumor size was 7.8 ± 3.7 cm (range, 2.4-16.2). HCC patients were intermediate stage BCLC B (n = 6), or advanced stage BCLC C (n = 1) due to portal vein tumor invasion. Six patients had cirrhosis. Neoadjuvant chemotherapy was concurrently given to 4/8 (50%) of the ICC patients. The average lobar dose was 198 ± 58 Gy and the average segmental boost dose was 186 ± 81 Gy, with an average of 1.6 segmental doses per patient. No severe adverse event from 90Y treatment occurred. Mean bilirubin was unchanged at 30-days. All patients had objective response at 30 days, including 6/15 (40%) with complete response and 9/15 (60%) with partial response. FLR increased by an average of 16.8% ± 14.6% at 30 days (n = 15), and 42.1% ± 22.8% at 90 days (n = 9). A total of 12/15 (80%) were eligible for surgical resection after treatment. One patient refused surgery and another developed concurrent breast cancer, thus 10/15 (67%) went on to hepatectomy (n = 9) or transplant (n = 1) with negative margins at a mean 122 ± 77 days post-treatment. Surgical resection included right (n = 4), extended right (n = 4), or extended left (n = 1) hepatectomies. The remaining 3 patients were ineligible for resection due to new disease progression in the contralateral liver lobe (n = 2) or to lungs (n = 1) at 1-, 2- and 3-months post-treatment. This study demonstrates that modified radiation lobectomy is safe and effective for treatment of HCC and ICC, with a high number of patients going on to definitive surgical management. This is an effective method to attain liver remnant hypertrophy while maintaining control over tumor progression.