SBRT with ≥70 Gy BED10 for colorectal liver metastases shows 74.5% 1-year FFLP

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Frontiers in Medicine Published April 19, 2026 Medically reviewed April 25, 2026 DOI ↗ By Dr. Julia Lee, PhD · Oncology, Genomics & Drug Development

Key Takeaway

Consider that higher PTV Dmin during SBRT for colorectal liver metastases may be associated with improved local control, but evidence is observational.

This was a retrospective, single-institution cohort study of 116 patients with 128 colorectal liver metastases treated with stereotactic body radiation therapy (SBRT) using a biologically effective dose (BED10) of ≥70 Gy. The median follow-up was 22.3 months. There was no reported comparator group.

The primary outcome was freedom from local progression (FFLP). The 1-year FFLP rate was 74.5%, and the 2-year FFLP rate was 58.8%. On multivariable analysis, a higher minimum planning target volume (PTV) dose was associated with improved FFLP (HR 0.89 per 10 Gy BED10, 95% CI 0.83–0.96, p = 0.002). Polymetastatic disease was associated with worse FFLP (HR 3.31, 95% CI 1.79–6.12, p < 0.001). When stratified by a PTV Dmin cut-point of 100 Gy BED10, the 1-year FFLP was 64.2% for low dose versus 87.1% for high dose (p < 0.001).

Safety and tolerability data were not reported. Key limitations include the retrospective, single-institution design and the absence of a comparator group. The practice relevance suggests that incorporating PTV Dmin into SBRT planning may improve FFLP beyond the nominal prescription dose. However, this is an observational study; associations do not imply causation, and findings are limited by study design.

Study Details

Study typeCohort

EvidenceLevel 3

PublishedApr 2026

View Original Abstract ↓

BackgroundThis 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).MethodsA total of 116 patients with 128 CLM treated with SBRT (≥70 Gy biologically effective dose [BED10]) 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.ResultsWith a median follow-up of 22.3 months, 1-year and 2-year FFLP rates were 74.5% and 58.8%, respectively. On univariable analyses, extent of metastasis, number of systemic therapy lines, pre- and post-SBRT carcinoembryonic antigen, PTV, prescription dose, and other plan parameters (Dmax, Dmin, Dmean, D2%, D95%, D98%, D99%) were significant. In the final multivariable model, PTV Dmin (HR 0.89 per 10 Gy BED10, 95% CI 0.83–0.96, p = 0.002) and polymetastatic disease (HR 3.31, 95% CI 1.79–6.12, p < 0.001) independently predicted FFLP. Using an optimal cut-point of 100 Gy BED10, low-PTV Dmin was associated with inferior FFLP compared with high-PTV Dmin (1-year: 64.2% vs. 87.1%, p < 0.001).ConclusionPTV Dmin emerged as the most robust dosimetric predictor of FFLP. Incorporating PTV Dmin into SBRT planning may improve FFLP beyond nominal prescription dose.