ESTRO 2021 Abstract Book

S998

ESTRO 2021

Conclusion Even though patients with a high CAC score in a univariable analysis had borderline significant reduced overall survival; this was not the case in the adjusted model. The univariable observation is likely related to correlations between PS, patient age, and high calcium. Risk stratification based on the current threshold does thus not seem informative. There may be a need to include the dose delivered to the heart to observe the impact of an elevated calcium level within the heart. PO-1202 Proton Beam Therapy for Stage I and Lymph Node-Negative Stage IIA Non-Small Cell Lung Cancer T. Asao 1 , K. Yasui 1 , N. Ota 1 , M. Shioi 1 , K. Hayashi 1 , S. Maki 1 , Y. Ito 1 , T. Onoe 1 , H. Ogawa 1 , H. Asakura 1 , S. Murayama 1 , T. Nishimura 1 , T. Takahashi 2 , Y. Ohde 3 , H. Harada 1 1 Shizuoka Cancer Center, Radiation and Proton Therapy Center, Nagaizumi-cho, Sunto-gun, Shizuoka Prefecture, Japan; 2 Shizuoka Cancer Center, Division of Thoracic Oncology, Nagaizumi-cho, Sunto-gun, Shizuoka Prefecture, Japan; 3 Shizuoka Cancer Center, Division of Thoracic Surgery, Nagaizumi-cho, Sunto- gun, Shizuoka Prefecture, Japan Purpose or Objective To examine disease control and survival after proton beam therapy (PBT) for Stage I and lymph node-negative Stage IIA non-small cell lung cancer (NSCLC). Materials and Methods