Mediastinal lymph node dissection in segmentectomy for peripheral c-stage IA (≤2 cm) non-small-cell lung cancer

Although recent trials on intentional segmentectomy have made mediastinal lymph node dissection (MLND) mandatory, the necessity of MLND in segmentectomy remains uncertain. We conducted a retrospective study to evaluate the necessity of MLND in segmentectomy for patients with peripheral stage IA (≤2 cm) non-small cell lung cancer.

Of the 5222 surgical cases for non-small cell lung cancer from 3 institutions between 2010 and 2021, 1457 patients met the JCOG0802 trial eligibility criteria. Initially, we analyzed 574 patients who underwent lobectomy with MLND to identify preoperative risk factors for cN0-pN2 occurrence (cohort 1). Subsequently, we evaluated the relationship between these factors and the cumulative postoperative recurrence in 390 patients who underwent segmentectomy (cohort 2).

In cohort 1, risk factors for cN0-pN2 occurrence were consolidation-to-tumor ratio = 1.0 and maximum standardized uptake value ≥2.0. When classifying patients into 3 groups (group A, without any factors, group B, with either factor, and group C, with both factors), the occurrence of cN0-pN2 was significantly greater in group C than in the other groups (0.9%, 3.4%, and 8.4%, respectively, P = .005). When classifying patients in cohort 2 using the classification identified in cohort 1 (117, 131, and 142 were categorized into group A, group B, and group C, respectively), the 5-year cumulative incidence of recurrence rate was significantly greater in group C than in others (2.0%, 2.0%, and 15.9%, respectively, P < .001).

MLND is unlikely to be beneficial in intentional segmentectomy for patients with tumors showing consolidation-to-tumor ratio <1.0 and maximum standardized uptake value <2.0.