Tumor Absorbed Dose Predicts Survival and Local Tumor Control in Colorectal Liver Metastases Treated with 90Y Radioembolization.

BACKGROUND

To evaluate predictors of outcomes in colorectal liver metastases (CLM) patients undergoing 90Y radioembolization (TARE), focusing on the impact of tumor absorbed dose.

MATERIALS AND METHODS

Patients' characteristics and dosimetry assessments were analyzed in 231 patients undergoing 329 TARE sessions from 09/2009 to 07/2023. Response was assessed using RECIST1.1 and PERCIST criteria.

RESULTS

Patients were predominantly male (137/231, 56.3%), had bilobar metastases (157/231, 68%) and received more than 3 lines of chemotherapy (144, 62.3%). Median age was 61 years (range 24-93). Glass and resin microspheres were used in 181/329(55%) and 148/329(45%) sessions, respectively. Weighted tumor absorbed dose covering at least 90% tumor (WTD90) ≥ 120 Gy (p = 0.043) and prior ablation (p = 0.016) were independent predictors of improved overall survival (OS) in the cohort. More than 10 CLMs (p < 0.001) and prior exposure to intra-arterial mitomycin-C (p = 0.015) were associated with decreased OS. Left colon (SHR: 1.680, 95% CI 1.136-2.484, p = 0.009) and rectal primary location (SHR: 1.586, 95% CI 1.005-2.504, p = 0.048) negatively impacted target liver progression-free survival (TLPFS), while intention to irradiate liver dose covering at least 50% tumor (ITILD50) had a positive impact (SHR: 0.955, 95% CI 0.926-0.984, p = 0.003) for the entire cohort. SIR Grade C and D complications were 1.2% and 2.7%, respectively, without correlation to dosimetry.

CONCLUSION

WTD ≥ 120 Gy was an independent predictor for improved OS after TARE for CLM regardless of microsphere type. High number of CLMs negatively impacted OS, while intention to irradiate liver dose covering at least 50% of the tumor positively impacted TLPFS.