Objectives: Limited studies analyzed prognosis of lung cancers as the secondary primary malignancy, but few of them compared extrapulmonary malignancies with lung cancers as the first primary malignancy or considered solid and sub-solid lung cancer nodules separately though they may have different prognosis. , consecutive cases of 1881 patients underwent curative surgery of lung cancer. Two hundred and fourteen patients with lung cancer as the secondary primary malignancy were included. The

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... chronous group were divided into the following two sub-groups. Group I, extrapulmonary malignant tumour as the first primary tumour (n = 62); group II, lung cancer as the first (n = 27). Consolidation/tumour ratio <0.5 were defined as ground-glass opacity (GGO)-dominant tumour. Results: The most two frequent types of extrapulmonary malignancy were breast cancer (18.5%) and colorectal (15.2%) cancer. The median interval between the diagnosis of lung cancer and the other malignancy was 100.8 months in group I and 68.3 months in group II, respectively (P = 0.09). More GGO-dominant lung cancers were found in group II than in group I (34.4% vs16.3%, P = 0.003). The 5-year overall survival (OS) were 56.5% for group I and 57.0% for group II (P = 0.97). Multivariate Cox analysis demonstrated advanced stage of lung cancer (hazard ratio [HR], 1.869; 95% confidence interval [CI], 1.338-2.611; P = 0.001) and age (HR: 1.072; 95% CI: 1.017-1.130; P = 0.009) were independent predictors of shorter overall survival for metachronous patients, while for synchronous patients were the advanced lung cancer stage (HR: 2.023; 95% CI: 1.036-3.948.8; P = 0.039) and extrapulmonary tumour history (HR: 1.122; 95% CI: 1.016-1.239; P = 0.023) with a 76.3% 5-year OS. Conclusion: This is the first study comparing patients with different characteristic lung cancers as the secondary primary malignancy. The clinical feature and prognosis were different between synchronous and metachronous MPC with lung cancers as the secondary primary malignancy. Disclosure: No significant relationships. Interactive CardioVascular and Thoracic Surgery