Validation of several SUV-based parameters derived from ¹⁸F-FDG PET for prediction of survival after SIRT of hepatic metastases from colorectal cancer

⁹⁰Y radioembolization (selective internal radiation therapy [SIRT]) is a valuable therapeutic option for unresectable hepatic metastases arising from primary colorectal cancer. The present study evaluated the prognostic value of ¹⁸F-FDG PET/CT metabolic parameters for predicting survival after SIRT. Methods: Eighty patients with hepatic metastases of colorectal cancer were treated with SIRT. ¹⁸F-FDG PET/CT was performed at baseline and 3 mo after the treatment. Metabolic volume, total lesion glycolysis, and maximum and peak standardized uptake value (SUV _max and SUV_peak, respectively) according to PET Response Criteria in Solid Tumors (PERCIST 1.0) were obtained from 3 liver lesions in each patient, and the corresponding percentage changes from baseline to follow-up were calculated. Tumor response was defined as more than a 30% decrease in these parameters. Furthermore, response was evaluated in accordance with Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Toxicity events and survival were recorded. Results: Overall median survival after SIRT was 60 wk. Responders who had a change in metabolic volume or total lesion glycolysis had significantly longer survival (92 vs. 49 wk [P = 0.006] and 91 vs. 48 wk [P = 0.025], respectively). However, neither RECIST 1.1 criteria nor changes in SUV_peak or SUV_max after treatment predicted outcome (P = 0.086 for RECIST; P = 0.310 for change in SUV_peak; P = 0.155 for change in SUV_max). Conclusion: Changes in metabolic volume and total lesion glycolytic rate as measured by ¹⁸F-FDG PET predicted survival in patients with hepatic metastases from colorectal cancer, whereas changes in SUV_peak or SUV_max and RECIST 1.1 criteria did not predict survival. COPYRIGHT