Background Patients with lung cancer subtypes such as adenocarcinoma in situ(AIS)or minimally invasive adenocarcinoma(MIA)can undergo limited resection,which preserves lung function,whereas those with invasive adenocarcinoma(IAC)require complete resection.Identification of factors that can predict these subtypes preoperatively is important for selecting the appropriate surgical procedure and for determining the postoperative survival.Methods We evaluated 87 patients with lung adenocarcinomas ≤30 mm.Ground-glass opacity(GGO)area on computed tomography scans,preoperative serum levels of carcinoembryonic antigen(CEA)and microRNA-183(miR-183),and tumour size correlated with histological subtype and overall survival.Results Preoperative radiological findings,serum CEA level,serum miR-183 level,tumour size,and visceral pleural invasion status differed significantly between patients with AIS or MIA and those with IAC(p < 0.001,= 0.015,0.042,< 0.001,and 0.003,respectively).Receiver operating characteristic curves and univariate analysis revealed that patients who were older than 57 years or had a pure solid nodule or a tumour with mixed GGO,a tumour > 11 mm,a serum CEA level > 2.12 ng/mL,or a serum miR-183 level >1.233(2-ΔΔCt)were more likely to be diagnosed with IAC than with AIS or MIA.The combination of all five factors had an area under the curve of 0.946,with a sensitivity of 89.13%and a specificity of 95.12%; the cut-off value for the five-factor combination was 0.499.Moreover,patients with a pure solid nodule or a tumour with mixed GGO,a tumour >11 mm,a serum CEA level >2.12 ng/mL,or a cut-off value >0.499 for the five-factor combination had poor overall survival(p = 0.0002,0.035,0.025,and 0.042,respectively).Conclusions The five-factor combination enables clinicians to distinguish AIS and MIA from IAC,thereby aiding in selecting the appropriate treatment(limited resection or adjusted therapy),and to predict the prognosis of lung adenocarcinoma patients.