Protocol of a single-arm, multicenter, phase III trial for selective lymph node dissection in cT1N0M0 invasive non-small cell lung cancer with consolidation-tumor ratio >0.5 located in the apical segment: Eastern Cooperative Thoracic Oncology Projects ECTOP-1018 (SELLAS study).

Background: Systemic lymph node dissection (LND) is the standard procedure for operable invasive non-small cell lung cancer (NSCLC), for radical cure and lymph node (LN) staging. However, its necessity is controversial in early-stage patients without LN metastasis, as evidence shows it could not improve prognosis and may cause surgical complications.

Methods: We initiated a prospective, multi-center, single-arm, phase III trial to confirm the non-inferior survival rate of surgery sparing the lower mediastinal LND in apical cT1N0M0 invasive NSCLC with consolidation-tumor ratio (CTR) >0.5 at high-resolution computed tomography (CT) scan. We plan to enroll a total of 634 patients with invasive NSCLC with predominantly non-lepidic subtype confirmed by intraoperative frozen pathology, who will receive radical lung cancer surgery but waiver lower mediastinal LND. The primary endpoint is recurrence-free survival (RFS), the secondary endpoints are overall survival (OS) rate of these patients, metastatic distribution of LNs in different histological subtypes of NSCLC, and consistency between frozen and paraffin pathology reports in determining the tumor invasiveness.

Discussion: The results of this study will validate the necessity of LND in the lower mediastinum in the patients with early-stage NSCLC located in the apical segment with CTR >0.5 at CT scan.

Trial registration: ClinicalTrials.gov Identifier NCT06031246.