3:27 PM Abstract No. 240 Glass and resin Yttrium-90 radioembolization of uveal melanoma hepatic metastases

Abstract

To evaluate hepatic progression free survival and overall survival of patients with metastatic uveal melanoma treated with yttrium-90 radioembolization using either glass or resin microspheres. Single center, retrospective 33-month review of 14 patients with metastatic uveal melanoma who received 23 radioembolization treatments (9 with glass and 14 with resin microspheres). In addition to demographic data, reviewed clinical variables included hepatic disease burden, prior locoregional therapy, extrahepatic metastatic disease, and peri-procedural immunotherapy. Calculated radiation dose to liver was determined for each procedure. Progression of hepatic disease was determined using the modified Response Evaluation Criteria in Solid Tumors (mRECIST). Overall survival and hepatic progression free survival were calculated from date of first treatment. Fewer patients treated with glass microspheres had bilobar disease (29 vs. 86%, P = 0.03); however, there was no significant difference in the number of lesions (86 vs. 100% with more than four lesions, P = 0.30) or largest lesion size (mean, 3.6 vs. 2.4 cm, P = 0.34) between the glass and resin groups. There was also no significant difference in prior locoregional therapy (86% vs. 57% had prior percutaneous ablation, P = 0.24), extrahepatic disease (P = 1.00) or immunotherapy regimens (P = 0.21). Calculated radiation dose to treated liver was significantly higher for the glass group (123.3 vs. 66.9 Gy, P <0.01). Hepatic progression free survival (median, 17.0 vs. 9.6 months, P = 0.02) and overall survival (median, 33.0 vs. 16.5 months, P = 0.05) were significantly longer for patients treated with glass microspheres. In this study, patients with liver dominant metastatic uveal melanoma treated with glass yttrium-90 microspheres demonstrated longer median hepatic progression free survival and overall survival compared to patients treated with resin yttrium-90 microspheres. This may be attributable to differing dose calculations based on the medical internal radiation dose (MIRD) model and body surface area (BSA) method respectively. Further analysis with a larger study population is warranted.