Prospective Trial Using Internal Pair-Production Positron Emission Tomography to Establish the Yttrium-90 Radioembolization Dose Required for Response of Hepatocellular Carcinoma

Publication date: 1 June 2018
Source:International Journal of Radiation Oncology*Biology*Physics, Volume 101, Issue 2
Author(s): Keith T. Chan, Adam M. Alessio, Guy E. Johnson, Sandeep Vaidya, Sharon W. Kwan, Wayne Monsky, Ann E. Wilson, David H. Lewis, Siddharth A. Padia
PurposeTo prospectively assess the threshold dose for objective response of hepatocellular carcinoma (HCC), using ⁹⁰Y internal pair-production positron emission tomography (PET) to quantify the radiation dose delivered to hepatic tumors after radioembolization.Methods and MaterialsA prospective study was performed under institutional review board approval from 2012 to 2014. Thirty-five patients with primary and secondary liver tumors undergoing ⁹⁰Y treatment were recruited. Eight patients did not meet inclusion criteria, and 27 patients with HCC were included for analysis. Time-of-flight PET imaging was performed immediately after radioembolization and voxel values converted into ⁹⁰Y activity. The radioembolization dose was calculated from PET images, and image segmentation was performed with volumetric analysis of dose deposition within tumors. Radiographic response was assessed on follow-up imaging.ResultsTreated HCC showed 84% objective response, 11% stable disease, and 5% progressive disease according to modified RECIST 1.1 response criteria. Responders had a higher median ⁹⁰Y tumor dose than nonresponders (225 Gy vs 83 Gy, P < .01). Logistic regression models show tumor dose (P = .002) strongly predicted objective response. All nonresponders had tumor dose <200 Gy. No statistical difference for patient age, tumor volume, multifocal or extrahepatic disease, portal vein invasion, or injected ⁹⁰Y activity was found between responders and nonresponders.ConclusionsHepatocellular carcinoma that resulted in objective response after radioembolization had a greater median tumor dose of 225 Gy, compared with 83 Gy in nonresponders. Delivered tumor dose can be assessed by PET and significantly impacts treatment response in HCC.



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