ESTRO 2025 - Abstract Book

S1421

Clinical - Lung

ESTRO 2025

Markers

CR

nCR

p value

HALP

33.96±14.02

27.16±12.15

0.047

LANR

12.91±5.41

9.91±4.54

0.028

SIRI

2.69±1.40

1.96±0.9

0.031

PIV

1460.00±1524.55

849.60±677.25

0.036

PAR

9.96±3.86

8.06±3.06

0.044

Table: Inflammatory markers by treatment response

Conclusion: NSCLC patients with lower pretreatment GRIm scores and higher HALP, LANR, SIRI, PAR, and PIV are more likely to have complete response to dCRT. These markers can be used to predict treatment response in patients with NSCLC undergoing definitive treatment with chemoradiation.

Keywords: NSCLC, chemoradiotherapy, inflammatory markers

3979

Digital Poster Dose Escalation with Simultaneous Integrated Boost Technique in Twice-Daily Radiation Therapy for Limited Stage Small Cell Lung Cancer (LS-SCLC) Sukran Senyurek 1 , Merve Duman 1 , Sena Birsen Guclu 2 , Duygu Sezen 1 , Nulifer Kilic Durankus 1 , Saliha Ezgi Oymak 3 , Nil Molinas Mandel 4 , Fatih Selcukbiricik 4 , Yasemin Bolukbasi 1 , Ugur Selek 1 1 Department of Radiation Oncology, Koc University, Istanbul, Turkey. 2 School of Medicine, Koc University, Istanbul, Turkey. 3 Department of Radiation Oncology, Amerikan Hospital, Istanbul, Turkey. 4 Department of Medical Oncology, Koc University, Istanbul, Turkey Purpose/Objective: The standard radiotherapy regimen for LS-SCLC was 45 Gy in 30 fractions delivered twice-daily, until the recent study published by Yu et al (1). This study indicated that escalating the dose up to 54 Gy provided to improve overall survival (OS) without increasing toxicity. However, real life routine practice data are scarce. We aimed to evaluate the survival in our cohort of patients who underwent dose escalation. Material/Methods: Patients with LS-SCLC who were treated with a twice-daily radiotherapy (TD-RT) regimen based on 4D-CT simulation with integrated tumor volume approach, appropriate heterogeneity correction software and intensity modulated radiotherapy planning, utilizing dose escalation via the Simultaneous Integrated Boost (SIB) technique, were analyzed retrospectively. The primary objective of the study is to evaluate OS outcomes. Secondary objectives include assessing disease-free survival (DFS) and toxicity outcomes. Results: From March 2010 to December 2023, a total of 92 patients who were treated with chemoradiotherapy for LS-SCLC were analyzed. Among these, 59 patients received dose escalation using the SIB in TD-RT.