Dimitrios Xenos

Background: Radiation segmentectomy (RS) is the selective trans-arterial delivery of an ablative dose of radiation to tumor-bearing hepatic segments, with the goal of complete tumor necrosis comparable to resection or thermal ablation. The technique was first described in patients with unresectable hepatocellular carcinoma (HCC). RS has since been applied to intrahepatic cholangiocarcinoma (iCCA) and to liver metastases of diverse origin, including colorectal, neuroendocrine, breast and sarcoma primaries. Purpose: To synthesize the original-data evidence base for RS across tumor types, to demonstrate the impact of tumor vascularity on tumor-specific dosimetry methods, and to define where the evidence supports standardization of methodology. Findings: Evidence is strongest for HCC, where pathologic-explant studies tie ablative dose thresholds to complete pathologic necrosis and prospective and large-cohort data demonstrate high response rates and extended patient survival. For colorectal liver metastases, several studies have associated tumor absorbed dose with response and local control. A single study additionally suggests that the dose delivered to the peritumoral margin is associated with local tumor control, an interesting hypothesis that requires further prospective validation. Data in iCCA and neuroendocrine metastases support feasibility and durable responses. The first international dosimetry consensus for non-HCC indications appeared in 2025. Heterogeneity in dosimetry models, dose thresholds, patient selection, and outcome reporting limits cross-study pooling. Conclusions: RS serves as a potentially curative locoregional therapy for selected patients with early-stage HCC and represents a promising treatment option for non-HCC tumors, especially for those not amenable to resection or thermal ablation. Histology-specific dosimetry, prospective validation, especially in non-HCC disease, and consensus reporting standards are necessary.

Purpose: This study examines the association between tumor volume doubling time (TVDT) and clinical outcomes for patients with hepatocellular carcinoma (HCC) treated with transarterial embolization (TAE) and evaluates the impact of tumor genotype on TVDT. Methods: This was a retrospective cohort study at a single tertiary care cancer center, including treatment-naïve patients with biopsy-proven HCC treated with TAE from 1/2014 to 6/2022. The patients underwent initial baseline contrast-enhanced cross-sectional imaging more than 30 days prior to embolization. Index tumors were defined as the largest HCC present on baseline imaging treated with TAE, and TVDT was calculated using Schwartz’s equation with perpendicular trans-axial measurements. Genetic mutation analysis was performed on HCC tissue specimens using next-generation sequencing. Survival analysis was performed using the Kaplan–Meier method, and Cox regression was used to assess prognostic factors for survival. Results: Patients with a TVDT ≤ 2.5 months had a worse overall survival (OS) after TAE (p = 0.011). On multivariate regression analysis, predictors of worse OS following TAE included TVDT ≤ 2.5 months (p = 0.036), Eastern Cooperative Oncology Group (ECOG) performance score of 1 or 2 (p = 0.006), and alpha fetoprotein > 200 ng/mL (p = 0.013). The presence of ≥5 HCC tumors on initial imaging was associated with a worse local tumor progression-free survival (LTPFS) on multivariate analysis (p = 0.002). No single genetic mutation was associated with shorter TVDT. Conclusion: Patients with HCC exhibiting rapid growth, defined as shorter TVDT, may be associated with worse overall survival following TAE. Rapid tumor growth does not seem to be correlated with a single genetic mutation.

Cancer is a leading cause of cancer-related death. Liver metastases develop in over one-third of patients and are associated with worse prognosis. The evolution in the field of interventional oncology/radiology over the past two decades has expanded image-guided locoregional therapies for colorectal liver metastases (CLM). Historically, hepatic resection was considered the only possible cure for selected patients with CLM. Current evidence supports thermal ablation (TA) as another locally curative treatment modality for small CLM that can be ablated with adequate margins. Other non-thermal ablative treatment options include Yttrium-90 (⁹⁰Y) radiation segmentectomy (RS), irreversible electroporation (IRE), and histotripsy, with an evolving role in the treatment of CLM. More extensive disease that is not amenable to resection or ablation can be treated with intra-arterial therapies (⁹⁰Y trans-arterial radioembolization (TARE) and trans-arterial chemoembolization (TACE)). This comprehensive review describes the evolution of interventional oncology treatments for CLM and examines the appropriate indications for each treatment modality.