8009 Background: JCOG0802/WJOG4607L confirmed the superiority of segmentectomy on overall survival (OS) over lobectomy for small-sized peripheral non-small cell lung cancer (NSCLC). However, it remains unclear whether technically demanding complex segmentectomy offers therapeutic efficacy compared to lobectomy, similar to simple segmentectomy. This study therefore aimed to evaluate the oncological outcomes of complex and simple segmentectomy compared to those of lobectomy using final analysis data from JCOG0802/WJOG4607L. Methods: Simple segmentectomy was defined as resection of the bilateral superior division (S 6 ), left lingular (S 4+5 ), or superior division (S 1-3 ); all other segmentectomies were defined as complex. The primary outcome was OS, and secondary outcomes were respiratory function, relapse-free survival (RFS), cumulative incidence of locoregional relapse, and lung cancer-specific death. To ensure comparability, a location-adjusted analysis was performed, separately comparing lobectomy to simple segmentectomy in patients with tumors in the bilateral S 6 , left S 1-3 , or S 4+5 , and to complex segmentectomy in patients with tumors in the right S 7-10 , S 1-3 , or left S 8-10 , S 1-3 . Results: 1106 patients were assigned to either lobectomy (n = 554) or segmentectomy (n = 552) including 318 complex and 234 simple segmentectomies. At a median follow-up of 10.5 years, the 10-year OS was 83.5% (95% CI: 78.8–87.3%), 83.5% (95% CI: 77.7–87.9%) and 79.8% (95% CI: 76.1–83.0%) for complex, simple segmentectomy, and lobectomy, respectively. In the location-adjusted analysis, the 10-year OS were 83.6% (95% CI: 78.9–87.3%) for complex segmentectomy and 79.2% (95% CI: 74.7–82.9%) for lobectomy (HR 0.839 95% CI 0.608–1.158). Similarly, 10-year OS were 82.9% (95% CI: 76.9–87.4%) for simple segmentectomy and 78.0% (95% CI: 72.5–82.6%) for lobectomy (HR 0.791 95% CI 0.540–1.158). The reduction of median forced expiratory volume in 1 second at 1 year was less after complex (−7.9%) and simple segmentectomy (−9.0%) than lobectomy (−12.0%; p < 0.001 and p < 0.001, respectively). RFS and lung cancer-specific death were not significantly different among the arms, while the cumulative incidence of locoregional relapse was higher after complex and simple segmentectomy than lobectomy (HR 2.124 95% CI 1.327–3.339 and HR 1.817 95% CI 1.071–3.083, respectively). Surgical margins were shorter in complex (median 2.2 cm, p < 0.001) and simple (2.5 cm, p < 0.001) segmentectomy than lobectomy (4.0 cm). Conclusions: Complex segmentectomy showed a trend toward improved OS compared to lobectomy in small-sized peripheral NSCLC similar to simple segmentectomy. However, due to a higher risk of locoregional relapse, complex segmentectomy should be performed with meticulous attention to securing adequate surgical margin. Clinical trial information: UMIN000002317.
Kamigaichi et al. (Thu,) studied this question.