ESTRO 2025 - Abstract Book

S405

Clinical - Biomarkers

ESTRO 2025

References: 1) Berger MF, Mardis ER. The emerging clinical relevance of genomics in cancer medicine. Nat Rev Clin Oncol . 2018;15(6):353-365. doi:10.1038/s41571-018-0002-6 2) Homer, J. J., Winter, S. C., Abbey, E. C. et al(2024). Head and Neck Cancer: United Kingdom National Multidisciplinary Guidelines, Sixth Edition. The Journal of laryngology and otology, 138(S1), S1–S224. https://doi.org/10.1017/S0022215123001615 3) Filetti S, Durante C, Hartl D et al. Thyroid cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and

follow-up. Ann Oncol2019;30(12):1856–83. doi:10.1093/annonc/mdz400 4) NHS England. National Genomic Test Directory for Cancer. 2024. Available at: https://www.england.nhs.uk/publication/national-genomic-test-directories/

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Digital Poster Immunological inflammatory biomarkers can serve as prognostic predictors for liver mCRC patients undergoing SBRT treatment. Kiril Zhelev Radiotherapy and Radiosurgery, Heart and Brain Center of Clinical Excellence, Pleven, Bulgaria Purpose/Objective: The immunological inflammatory biomarkers for liver metastatic colorectal cancer (mCRC) are unclear. We aimed to investigate the relationship between the immune system and inflammation levels and the outcomes of Stereotactic body radiation therapy (SBRT) for the liver in patients with oligometastatic colorectal cancer receiving SBRT as their primary treatment. Material/Methods: Between 2022 and 2024, we enrolled 82 consecutive patients with liver mCRC who received liver SBRT as primary treatment in the "Heart and Brain Center of Clinical Excellence" in Pleven. We evaluated the changes in the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) before treatment and their impact on survival. We calculated the cut-off values of NLR and PLR for predicting overall and progression-free survival using receiver Kaplan-Meier estimation and Cox regression. Results: A total of 82 patients were men, 42 (51.2%) and women, 40 (48.8%), with a median age of 65±9.6. Patients with Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 were 29 (35.4%) and PS 1–53 (64.6%). Increased NLR was present in 42 (51.2%) patients and increased PLR in 39 (47.6%) patients. Patients with increased NLR had a significantly shorter mean PFS (13.44 months, 95% CI: 11.42–15.01 vs. 29.63 months, 95% CI: 27.47–31.80; p<0.001) and shorter mean OS (26.11 months, 95% CI: 22.57–29.62 vs. 30.96 months, 95% CI: 29.59–32.39; p = 0.002) than patients with decreased NLR. Patients with increased PLR had a significantly shorter mean PFS (13.44 months, 95% CI: 11.43-15.43 vs 28.86 months, 95% CI: 26.32-31.40; p<0.001) and shorter mean OS (26.28 months, 95% CI: 23.06-29.50; vs 32.22 months, 95% CI: 29.25-35.18; p=0.045) than patients with decreased PLR. Univariate analysis identified NLR, PLR, and Child-Pugh class as prognostic factors for PFS after SBRT. Multivariate Cox regression analysis demonstrated that PLR and NLR were independent prognostic factors for PFS, even when corrected for the Child-Pugh class. Univariate analysis identified NLR, PLR, and the Child-Pugh class as prognostic factors for OS after SBRT. Multivariate Cox regression analysis revealed that only the NLR was an independent prognostic factor for OS, even when correcting for the PLR and Child-Pugh classes.