The extent of lymph node dissection is not associated with disease-free survival following lobar or sublobar resection: Results from Cancer and Leukemia Group B 140503 (Alliance)

Objective

The extent of lymphadenectomy in patients with c-stage I non–small cell lung cancer is controversial. Cancer and Leukemia Group B 140503 (Alliance; NCT00499330) randomized patients with peripheral clinical stage 1A non–small cell lung cancer 2 cm or less to lobar or sublobar resection after frozen-section examination of 2 mediastinal nodes and 1 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, systematic sampling, or complete lymph node dissection. We report the impact of the extent of lymphadenectomy on disease- and recurrence-free survival in this trial.

Methods

Between June 2007 and March 2017, 697 patients were randomized to lobar resection (357) or sublobar resection (340). Data on the extent of lymphadenectomy were available on 689 patients: A total of 182 patients had complete lymph node dissection, 349 patients had systematic sampling, and 158 patients had simple sampling. Disease-free survival was defined as the time to lung cancer recurrence or all-cause mortality. Recurrence-free survival was defined as the time to lung cancer recurrence or death from lung cancer. Survival end points were estimated using the Kaplan–Meier method. Stratified Cox proportional hazards models estimated hazard ratios and their CIs.

Results

Baseline characteristics were generally similar between groups. Five-year disease-free survival was 62.3% (95% CI, 55.2-70.4) after complete lymph node dissection, 65.7% (95% CI, 60.7-71.2) after systematic sampling, and 61.2% (95% CI, 53.7-69.7) after simple sampling. Disease-free survival was not statistically significantly different between lobar resection and sublobar resection based on the extent of node dissection. Five-year disease-free survival among patients who had complete lymph node dissection was 65.7% (95% CI, 56.4-76.6) after lobar resection and 58.5% (95% CI, 48.2-71.1) after sublobar resection (P = .530). Five-year disease-free survival in patients who had simple sampling/systematic sampling was 63.5% (95% CI, 57.6-70.0) after lobar resection and 65.1% (95% CI, 59.2-71.6) after sublobar resection. Five-year recurrence-free survival for patients who had complete lymph node dissection was 72.5% (95% CI, 63.5-82.9) after lobar resection and 68.9% (95% CI, 59.0-80.5) after sublobar resection (P = .526). Five-year recurrence-free survival in patients who had simple sampling/systematic sampling was 70.8% (95% CI, 65.0-77.0) after lobar resection and 70.2% (95% CI, 64.4-76.5) after sublobar resection (P = .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 non–small cell lung cancer 2 cm or less in size who have no nodal metastases to at least 2 mediastinal nodes and 1 major hilar lymph node, there is no difference in disease-free survival or recurrence-free survival 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