8:56 AM Abstract No. 66 - Survival after radioembolization for metastatic colorectal cancer: search for prognostic factors

Purpose Investigate clinical and procedural variables to determine if there is a correlation with survival after treatment with radioembolization for metastatic colorectal cancer (mCRC). Materials and Methods Retrospective review was performed of patients treated with Y-90 radioembolization for mCRC at our institution between May 2008 and March 2012. Survival after radioembolization was the primary outcome variable. Variables studied included age, cancer stage, disease extent at treatment, tumor grade, treatment line of radioembolization, chemotherapy with or without bevacizumab (Avastin), time of the last bevacizumab dose to radioembolization date, tumor-to-normal liver vascularity ratio (TNVR), tumor volume, total target tumor dose, and total normal liver dose. Cox proportional hazards models were fitted to the data and Kaplan-Meier curves were drawn. Results Thirty nine patients (22 M, 17 F) met the inclusion criteria with mean age of 64.1 years. Thirty one subjects expired at the time of the study. Presentation with mCRC at their initial diagnosis occurred in 25 subjects. Only hepatic metastatic disease was present in 23 patients. Bevacizumab pre-treatment occurred in 30 subjects. The mean values of total tumor volume (245±339 cc), highest tumor-to-lobe volume fraction (21.6±19.8%), total target tumor dose (272±202 Gray), total normal liver dose (89.6±74.5 Gray), and TNVR (3.2±0.8) are calculated. The mean survival from the first Y-90 infusion was 13.9±10.9 months and mean survival from mCRC diagnosis was 31.4±16.6 months. Treatment line of radioembolization had strongest correlation with survival and hazard ratios compared to first-line are 1.4, 22, and 87 are seen with second-line, third-line, and salvage (>3rd line) therapies, respectively. Also, the only other variables with statistically significant correlations were age, hepatic only vs. extra-hepatic disease extent, and tumor-to-lobe volume fraction of the most burdened hepatic lobe. Conclusion Age, disease extent, treatment line of radioembolization, and the tumor-to-lobe volume fraction had significant correlations with survival after radioembolization for mCRC. Survival compares favorably to historical survival after modern chemotherapy alone.