Long-term outcomes of stage I NSCLC (≤3 cm) patients following segmentectomy are equivalent to lobectomy under analogous extent of lymph node removal: a PSM based analysis

Background: Segmentectomy has the advantage of less complications, but might have less lymph node sampling and higher risk of recurrence. We aimed to compare treatment outcome between two surgical options, and explore the effect of regional lymph node removal on the prognostic difference. Methods: We retrospectively analyzed data of stage I non-small cell lung cancer (NSCLC) (<= 3 cm in size) patients who underwent either segmentectomy, or lobectomy, collected from the Surveillance, Epidemiology and End Results (SEER) database, from 2003 to 2013. The primary endpoints were overall survival (OS) and lung cancer-specific survival (LCSS). We also collected data from Shandong Provincial Hospital as validation. Results: Ultimately 1,156 patients treated by segmentectomy and 17,748 patients treated by lobectomy from SEER database were included in the analysis. Overall, segmentectomy was inferior to lobectomy in terms of OS [hazard ratio (HR): 1.316 (1.186-1.461), P< 0.001] and LCSS [HR: 1.310 (1.142-1.504), P< 0.001]. When the removal of regional lymph nodes (LN) was taken into consideration, no significant difference was found in OS and LCSS, in any Scope of Regional Lymph Node Surgery layer (0, 1-3, more than 3, and biopsy/sentinel layer, all P> 0.05). After propensity score matching (PSM), there was no difference between segmentectomy and lobectomy in OS [HR: 1.081 (0.937-1.248), P= 0.286] and LCSS [HR: 1.039 (0.861-1.253), P= 0.692]. Only sex, age, histology, summary stage, differentiation, tumor size, and radiation still remained as independent prognostic factors for both OS and LCSS. For validation part, there was no significantly prognostic difference between lobectomy and sublobectomy group in overall (P= 0.132) and each regional LN removed layer (0, 1-3, more than 3 layers: all P> 0.05). Conclusions: Segmentectomy with proper lymph node resection or sampling could be a good alternative to lobectomy.