Risk of recurrence in stage I adenocarcinoma of the lung: A multi-institutional study on synergism between type of surgery and type of nodal staging

Background: In last years, an increasing interest emerges on the role of sub-lobar resection and lobe-specific lymph nodal dissection in the treatment of early-stage lung cancer. The aim of our study was to define the impact On cumulative incidence of recurrence (CIR) of type of surgical resection and type of nodal staging in this subset of patients. Furthermore, we evaluated the possible synergism between the different kinds of procedure. Methods: An analysis of 969 consecutive stage I pulmonary adenocarcinoma patients, operated in six Thoracic Surgery Institutions between 2001 and 2013, was conducted. Type of surgical resection included lobectomy and sub-lobar resection; while pneumonectomy and bilobectomy were excluded from the analysis. Nodal staging procedures were classified in nodal sampling (NS), lobe-specific lymph node dissection (LS-ND) and systematic lymph node dissection (SND). Multivariable-adjusted comparisons for CIR was performed using Fine and Grey model, taking into account of death by any cause as competing event. In order to evaluate synergism between the different procedures, the test of interaction between type of surgical resection and type of nodal staging was carried out and results presented in a stratified way. Results: Eight-hundred forty-six (87%) patients were submitted to lobectomy, while 123 (13%) to sub-lobar resection. Four-hundred fifty-five (47%) patients received SND, 98 (10%) LS-ND and 416 (43%) NS. Two-hundred forty-seven (26%) patients developed a local/distant recurrence with a 5-year CIR of 24.2%. Multivariable-adjusted comparisons showed an independent negative effect of sub-lobar resection (HR =1.52; 95% CI: 1.07-2.17), LS-ND (FIR =1.74; 95% CI: 1.16-2.6) and NS (UR =1.49; 95% CI: 1.12-1.98) on CIR. Test of interaction showed a homogeneity of results among subgroups. Conclusions: Patients affected by stage I pulmonary adenocarcinoma and submitted to lobectomy presented a significant lower recurrence rate than those submitted to sub-lobar resection. Moreover, SND presented an independent positive effect on recurrence development than other lymph node assessment strategy. Finally, lobectomy in combination with systematic lymph nodal resection showed the best results in term of CIR.