OBJECTIVETo evaluate the prognostic significance of a new grading and scoring system (based on the new IASLC/ATS/ERS classification) in stage I pulmonary adenocarcinoma, as compared with the WHO grading system.

METHODSThe clinicopathologic characteristics of 125 patients with stage I pulmonary adenocarcinoma primarily treated by surgical resection were reviewed retrospectively. All cases were classified according to the new IASLC/ATS/ERS classification and graded into three prognostic groups based on the new classification, the Sica scoring system and the WHO grading system, respectively. The differences in prognosis of the three groups were analyzed.

RESULTSThere was a statistically significant correlation between the new grading system and the WHO grading system (P = 0.000). Both of them showed negative correlation with overall survival. The new scoring system however better correlated with disease recurrence and/or metastasis (P = 0.855, P = 0.073 versus P = 0.011). According to univariate Log-rank test, the prognosis correlated with tumor size (P = 0.004), clinical stage (P = 0.000), the WHO grading (P = 0.020), the new grading system (P = 0.000), the new scoring system (P = 0.000), vascular invasion (P = 0.021), and recurrence and/or metastasis (P = 0.000). The Cox regression analysis demonstrated that clinical stage (P = 0.014), the new grading system (P = 0.047), the new scoring system (P = 0.043), and recurrence and/or metastasis (P = 0.018) were significantly independent poor prognostic factors.

CONCLUSIONSThe new grading and scoring system shows good correlation with the WHO grading system. Compared with the WHO grading system, the new scoring system based on the new IASLC/ATS/ERS classification provides valuable information in categorizing stage I pulmonary adenocarcinoma cases with different risks of disease recurrence, tumor metastasis and prognosis.