The management of colorectal cancer (CRC) liver metastases with yttrium-90 microspheres (Y90): The south Australian (SA) experience

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Background: Treatment of CRC liver metastases with Y90 may provide a survival benefit but remains under investigation. We report on the accumulated SA clinical experience of using Y90 in the treatment of patients with metastatic CRC. Methods: Data from the SA mCRC Database was used to analyse the baseline characteristics of patients treated with Y90 to determine patterns of care. Safety and adverse outcomes, tumour response, disease progression, and survival were also examined. Survival outcomes were analysed using Kaplan Meier estimates, and chi square testing used for comparisons. Results: 33 patients received Y90, with median age 67 (range 33-83), 25 male, 29 colon/4 rectal primary, 25 hepatic only metastatic disease. Systemic therapy pre Y90 was as follows; nil=4, 1 line=7, 2 lines=9, ≥3=11, unknown=2. There were no immediate Grade III/IV adverse events, though immediate toxicity occurred in 9 patients; liver capsule pain in 8, chest pain and vomiting in 1 patient. Following Y90 treatment, radiologist reported response showed: measurable reduction =3 (ORR 9%), SD=4, PD=20, and 1 patient unknown. Treatment beyond Y90; nil=16 patients, 1 line=7, 2 lines=7 and >3=2 patients. Data on hepatic progression free survival (PFS) and overall PFS is currently being analysed. Median survival from the time of Y90 treatment was 10.3 months. Conclusions: Our data show Y90 use in SA occurs most often after 2 lines of chemotherapy. No immediate grade 3/4 toxicity was encountered. Survival for this select group appears longer than expected. Data on mOS from delivery of Y90, hepatic PFS and overall PFS for subgroups will be reported.