Cold-spot driven local failure after stereotactic body radiation therapy for colorectal liver metastases

Background: This single-institution retrospective study investigated whether actual dosimetric plan quality metrics better predict freedom from local progression (FFLP) than nominal prescription dose after stereotactic body radiation therapy (SBRT) for colorectal liver metastases (CLM). Methods: ]) were retrospectively analyzed. Clinical variables and dosimetric factors, including maximum, minimum, and mean doses (Dmax, Dmin, Dmean), as well as dose to x% of the planning target volume (PTV) (Dx%), were evaluated. Cox regression analyses and the Akaike information criterion were used to identify prognostic factors for FFLP. Results: , low-PTV Dmin was associated with inferior FFLP compared with high-PTV Dmin (1-year: 64.2% vs. 87.1%, p < 0.001). Conclusion: PTV Dmin emerged as the most robust dosimetric predictor of FFLP. Incorporating PTV Dmin into SBRT planning may improve FFLP beyond nominal prescription dose.