The prognostic value of lymph node ratio and log odds of positive lymph nodes in patients with lung adenocarcinoma

Abstract Objective To investigate whether lymph node ratio and log odds ratio can be used for predicting the prognosis of patients with lung adenocarcinoma. Methods A total of 1097 patients with lung adenocarcinoma who underwent complete surgical resection and systematic lymph node dissection between 2008 and 2013 were studied retrospectively. Lymph node ratio was calculated as: positive lymph nodes  total lymph nodes  . Log odds ratio was calculated as: log positivelymph nodes + 0.5 total lymph nodes − positive lymph nodes + 0.5 . Patients were grouped respectively into 4 groups by the use of recursive partitioning according to their lymph node ratio and log odds ratio. Linear trend χ 2 test was used for measuring monotonicity and discriminatory power. Results The 3-year survival rate was 91.0% (89.9%-92.1%) for group 0, 75.2% (71.4%-79.0%) for group 1, 56.5% (51.5%-61.5%) for group 2, and 41.4% (36.4%-46.4%) for group 3 of lymph node ratio, respectively. In addition, the 3-year survival rate was 89.9% (88.7%-91.1%) for group 1, 78.4% (74.4%-82.4%) for group 2, 56.0% (50.9%-61.1%) for group 3, and 41.0% (36.1%-45.9%) for group 4 of log odds ratio, respectively. Univariable and multivariable Cox models identified that both lymph node ratio and log odds ratio were significant prognostic factors for patients' survival. Log-rank test of trend χ 2 statistics of both lymph node ratio ( P P Conclusions Both lymph node ratio and log odds ratio can be used as prognostic factors for clinicians to predict patients' prognosis.