Omitting of Lymphadenectomy is Acceptable for Lung Cancer Smaller Than 6 mm in Solid Size

Many studies suggested that selective lymph node sampling was acceptable for specific non-small cell lung cancer (NSCLC). This study aimed to evaluate the acceptability of omitting of lymphadenectomy for selected NSCLC.

Patients with small-sized (≤2 cm) NSCLC who underwent surgical resection between 2009 and 2022 were retrospectively screened. The characteristics of patients with nodal metastasis were demonstrated. For selected patients, the perioperative and long-term outcomes of patients with and without lymphadenectomy were compared. Log-rank test and Cox regression analysis were adopted for prognostic evaluation.

A total of 2713 NSCLC patients were enrolled, and 75 of them (2.76%) had nodal involvement. None of patients with pure ground glass opacity (0/945) had nodal metastasis, while 14 patients with part-solid (14/1260, 1.11%) and 61 patients with solid nodules (61/508, 12.01%) had nodal involvement. Patients with nodal metastasis had a minimum solid size of 6 mm. NSCLC with solid components < 6 mm (n=1588) had no nodal metastasis. Of them, 339 patients underwent sublobar resection without lymphadenectomy (SRN0), 1056 subjects received sublobar resection with lymphadenectomy (SRN1), and 190 patients received lobectomy plus lymphadenectomy (LRN1). Patients with SRN0 had a shorter operating time, less volume of drainage, a lower incidence of chylothorax (0 vs. 0.6% vs. 2.1%, P=0.012) and air leakage, as well as a shorter postoperative hospitalization (3 vs. 4 vs. 4 days, P<0.001) than those with SRN1 or LRN1. During a median follow-up of 61 months, no patient with SRN0 was dead or tumor recurrent. The 5-year recurrence-free survival was 100%, 99.2% and 98.5% for patients with SRN0, SRN1 and LRN1, respectively (P=0.370).