The Prognostic Significance of Metastasis to Lymph Nodes in Aortopulmonary Zone (Stations 5 and 6) in Completely Resected Left Upper Lobe Tumors.

Introduction: We investigated the prognostic effect of lymph nodes metastasis in aortopulmonary (AP) zone in resected non-small cell lung cancer of the left upper lobe (LUL).

Methods: Between 1998 and 2010, 181 patients with LUL carcinoma underwent complete resection and were retrospectively analyzed. The patients were divided into four groups according to N status: N0 (n = 68, 37.6%), N1 (n = 64, 35.3%), N2(5,6+) (only metastasized to stations 5 and/or 6, n = 36, 19.9%), and N2(7+) (only metastasized to stations 7, n = 13, 7.2%). N1 were divided according to single and multiple (N1(single) n = 49, N1(multiple) n = 15) or peripheral and hilar (N1(peripheral) n = 39, N1(hilar) n = 25).

Results: Overall 5-year survival rate was 55.1%. Five-year survivals were 76.1% for N0, 54.3% for N1, and 20.7% for N2. N1(peripheral) had a better survival than N1(hilar) (60.3 vs. 29.4%, p = 0.09). Five-year survival of N1(single) was 60.1%, whereas it was 36.6% for N1(multiple) (p = 0.02). Five-year survival rate was 24.6% for N2(5,6+). Skip metastasis for lymph nodes in AP zone (n = 13) was a factor of better prognosis as compared to nonskip metastasis (n = 23) (29.9 vs. 19.2%). There was no statistically significant difference between the N2(5,6+) and N1(hilar) (p = 0.772), although N1(peripheral) had a significantly better survival than N2(5,6+) (p = 0.02). AP zone metastases alone had a significantly worse survival than N1(single) (p = 0.008), whereas there was no statistically significant difference between the N1(multiple) and N2(5,6+) (p = 0.248). N2(7+) was not expected to survive 3 years after operation. They had a significantly worse prognosis than N2(5,6+) (p = 0.02).

Conclusion: LUL tumors with metastasis in the AP zone lymph nodes, especially skip metastasis, were associated with a more favorable prognosis than other mediastinal lymph nodes. However, the therapy of choice for lung cancer with N2(5,6+) has not been clarified yet.