ESTRO 2021 Abstract Book

S955

ESTRO 2021

DM. Overall, DM (mainly bone sites) developed in 5 patients (3.8%). Four of the 5 patients with DM had Luminal B molecular subtype (HER2-). One cancer-related death (0.7%) occurred in the pN1a group, none in the pN1mic group.

Conclusion Actually, we are confident about WBRT in Z0011 patients characteristics, without nodal surgery or RT, despite initial criticism. In cT1-2 cN0 BC patients with 1 or 2 positive SLN treated with BCS our results showed good regional disease control avoiding axillary morbidity. Our follow-up is still ongoing for all the treated patients.

Digital Poster: Lung

PO-1148 Post-Operative Radiotherapy in completely resected Non-Small Cell Lung Cancer and N2 involvement A.M. Pires 1 , T. Figueiredo 1 , S. Conde 1 , C. Ferreira 1 , A. Laranja 1 , B. de Castro 1 , F. Sousa 1 , S. Sarandão 1 , J. Cardia 1 1 IPO Porto, Radiation Oncology, Porto, Portugal Purpose or Objective The benefit of post-operative radiotherapy (PORT) in patients with completely resected non-small cell lung cancer (NSCLC) remains controversial. Recent improvements in patient selection, staging, surgical quality, standard use of (neo)adjuvant chemotherapy (ChT) and radiotherapy (RT) techniques may lead to an improvement in the outcomes. To clarify this uncertainty, the LungART trial is underway, which served as the basis for our study. The authors describe the experience of a RT service in PORT in patients with stage N2 NSCLC and assess the possible relation between clinical-pathological factors in disease-free survival (DFS), regional-DFS (R-DFS) and overall survival (OS). Materials and Methods Retrospective cohort study of patients with NSCLC stage IIIA (cN2 or pN2) treated in a RT service between jan/2013 and dec/2018. Patients who underwent complete tumor resection and mediastinal nodal exploration were included. (Neo)adjuvant ChT was allowed. Patients with disease progression during adjuvant ChT were excluded. Clinicodemographic and treatment data were collected. DFS, R-DFS and OS were assessed using univariate and multivariate Cox regression models.