ESTRO 2023 - Abstract Book

S1064

Digital Posters

ESTRO 2023

Conclusion Risk-adaptive SBRT for UC tumors is safe and effective even if it remains a high-risk clinical scenario. Patients with larger tumor , elderly and male patients treated for UC lung tumors report a worse OS and should carefully evaluated for treatment eligibility.

PO-1330 Comparison between proton and photon beam therapy for limited-stage small cell lung cancer

S.H. Seo 1 , H. Pyo 1 , Y.C. Ahn 1 , D. Oh 1 , K. Yang 1 , N. Kim 1 , J.M. Noh 1

1 Samsung Medical Center, Sungkyunkwan University School of Medicine, Radiation Oncology, Seoul, Korea Republic of

Purpose or Objective Proton beam therapy (PBT) has been increasingly used as a definitive treatment of patients with lung cancer. However, there are limited data on its efficacy and safety in patients with small cell lung cancer (SCLC). Herein, we aimed to evaluate oncological outcomes and toxicities of definitive PBT compared to photon beam therapy in patients with LS (limited stage)- SCLC. Materials and Methods We retrospectively reviewed 262 patients who received definitive PBT (n=20) or photon beam therapy (n=242) with concurrent chemotherapy for newly diagnosed LS-SCLC from January 2016 to February 2021. Overall survival (OS) and progression-free survival (PFS) were compared, and dose-volume parameters were also compared. Results The median follow-up duration was 23.2 months (range, 2.1-76.8). Patients receiving PBT had worse lung function at baseline in terms of FEV1<50% (20.0% versus 2.9%, P=0.012) and DLCO<60% (45.0% versus 16.1%, P=0.011) compared to those receiving photon beam therapy. In addition, patients treated with PBT more frequently had clinical target volume (CTV)