The extent of lymph node dissection is not associated with disease-free survival following lobar or sublobar resection: results from CALGB 140503 (Alliance).

OBJECTIVE

The extent of lymphadenectomy (LAD) in patients with c-stage I non-small cell lung cancer (NSCLC) is controversial. CALGB 140503 (Alliance; NCT00499330) randomized patients with peripheral clinical stage 1A NSCLC ≤ 2 cm to lobar (LR) or sublobar resection (SLR) after frozen section examination of 2 mediastinal and one major hilar node (simple sampling) confirmed the absence of nodal metastases. Additional node dissection was performed at the surgeon's discretion and included simple sampling (S), systematic sampling (SS), or complete lymph node dissection (CLND). Here, we report the impact of the extent of LAD on disease- and recurrence-free survival (DFS and RFS) in this trial.

METHODS

Between 6/2007 and 3/2017, 697 patients were randomized to LR (357) or SLR (340). Data on the extent of lymphadenectomy was available on 689 patients: 182 had CLND, 349 had SS, and 158 had S. DFS was defined as the time to lung cancer (LC) recurrence or all-cause mortality. RFS was defined as the time to LC recurrence or death from LC. Survival endpoints were estimated using the Kaplan-Meier method. Stratified Cox proportional hazards (PH) models estimated hazard ratios and their confidence intervals (CI).

RESULTS

Baseline characteristics were generally similar between groups. Five-year DFS was 62.3% (95%CI: 55.2 - 70.4%) after CLND, 65.7% (95%CI: 60.7 - 71.2%) after SS, and 61.2% (95%CI: 53.7 - 69.7%) after S. DFS was not statistically significantly different between LR and SLR based on the extent of node dissection. Five-year DFS among patients who had CLND was 65.7% (95%CI: 56.4 - 76.6%) after LR and 58.5% (95%CI: 48.2 - 71.1%) after SLR (p=0.530). Five-year DFS in patients who had S/SS was 63.5% (95%CI: 57.6 - 70.0%) after LR and 65.1% (95%CI: 59.2 - 71.6%) after SLR). Five-year RFS for patients who had CLND was 72.5% (95% CI: 63.5 - 82.9%) after LR and 68.9% (95%CI: 59.0 - 80.5%) after SLR (p=0.526). Five-year RFS in pts who had S/SS was 70.8% (95%CI: 65.0 - 77.0%) after LR and 70.2% (95%CI: 64.4 - 76.5%) after SLR (p=0.604). There was no difference between groups in the incidence of systemic recurrence or isolated hilar, mediastinal, or supraclavicular nodal recurrence.

CONCLUSIONS

In patients with peripheral c-stage IA NSCLC ≤ 2 cm in size who have no nodal metastases to at least two mediastinal and one major hilar lymph nodes, there is no difference in DFS or RFS based on the extent of lymph node dissection, regardless of the magnitude of parenchymal resection. Our findings apply to a highly selected cohort of patients deemed node negative by meticulous radiographic and intraoperative nodal staging.