e18551 Background: Radiotherapy plays an important role in the management of limited-disease small-cell lung cancer (LD-SCLC). However, volume of irradiation remains unanswered as well as optimal total dose, timing and sequencing of radiation. In this study, we compared the clinical lymph node staging with pathological staging, with the aim of investigating the safety of CT-based selective nodal irradiation for clinical stage N0-1 LD-SCLC patients. Methods: From July 2004 to March 2012, 20 potentially operable patients with clinical stage N0-1 LD-SCLC underwent contrast-enhanced CT scans and other routine initial staging procedures followed by radical resection of primary tumor and systemic intra-thoracic lymph node dissection. The results of reviewing clinical staging for the mediastinal lymph node metastases were compared with pathologic findings. Results: Preoperative nodal staging was compared with postoperative pathological staging, 35% (7 of 20) of patients were under staged by clinical staging. Of all the 7 patients with mediastinal lymph node metastases, 4 patients (57.1%) had subcrinal nodes (station 7) metastases, 1 had right upper paratracheal nodes (station 2R) metastases, 1 had left lower paratracheal nodes (station 4L) metastases, 1 had aortopulmonary nodes (station 5) metastases. Conclusions: CT-based selective nodal irradiation for LD-SCLC may result in geographical miss in clinical stage N0-1 patients. Mediastinal lymph node regions especially the subcrinal nodes should be contained in the clinical target volume for radiotherapy.