Abstract
PURPOSE: To investigate whether the presence of micropapillary and solid patterns are associated with nodal upstaging and survival patterns in patients with cT1N0M0 lung adenocarcinoma. METHOD: We retrospectively analyzed the clinicopathologic data of 2571 patients undergoing lobectomy and lymph node dissection or sampling. Logistic and Cox regression analysis were applied to determine the association between histological patterns and nodal upstaging and survival. RESULTS: Nodal upstaging was detected in 115 patients (4.5%) through postoperative pathologic examination. Tumors absent of lepidic pattern, and present with acinar, micropapillary and solid patterns had significantly higher nodal upstaging rate (all P < 0.001). Presence of micropapillary [odds ratios (ORs) = 3.51; 95% confidence intervals (CI) = 2.09-5.89; P < 0.001] and solid (OR 2.28; 95% CI 1.42-3.64; P = 0.001) patterns were independent predictors for nodal upstaging. Presence of micropapillary and solid patterns also significantly deteriorated the recurrence-free survival (RFS) (both log-rank P < 0.001), and were independently associated with unfavorable RFS in multivariable Cox analysis RFS [micropapillary: hazard ratios (HR) = 1.41; 95% CI 1.04-1.99; P = 0.041; solid: HR 2.05; 95% CI 1.56-2.70; P < 0.001]. CONCLUSION: The analysis of a large-scale cohort demonstrated that the presence of micropapillary and solid patterns significantly increase the risk of nodal upstaging and are independently associated with unfavorable prognosis.