Impact of previous extra-pulmonary malignancies on surgical outcomes of sequential primary non-small cell lung cancer

Reduced cancer deaths have led to an increase in the number of cancer survivors and the risk of the second primary tumor. This study explored the surgical outcomes of patients with non-small cell lung cancer as the second primary tumor and the impact of previous extra-pulmonary malignancies. Patients’ data were obtained from Surveillance, Epidemiology and End Results database. The patients were divided into lung surgery and non-surgery groups. Propensity-score matching was used to balance potential confounders. Kaplan-Meier curves were generated to test the overall survival and lung-cancer-specific survival. Cox regression analysis was performed to calculate death risk. In total 3054 lung surgery and 1094 non-surgery patients with stage I-II non-small cell lung cancer as the second primary tumor were included. The surgery group showed longer overall survival (68 vs. 22 months) and lung cancer-specific survival (not reached vs. 37 months) than those of non-surgery groups (both P < 0.001). Patients with previous hormone-dependent malignancies had similar survival rates (overall survival: 22 vs. 20 months, P = 0.666; lung cancer-specific survival: 38 vs. 37 months, P = 0.292) as those with non-hormone dependent malignancies in the non-surgery group. Significantly longer overall survival (90 vs. 60 months, P = 0.001) was observed in patients with hormone-dependent malignancies in the surgery group; however, there was no difference in lung cancer-specific survival (P = 0.225). Competing risk analysis showed that for patients undergoing lung surgery, there was higher previous malignancy-induced mortality in patients with non-hormone dependent malignancies than in patients with hormone-dependent malignancies. However, there was no difference in lung cancer-induced mortality between the two groups. Patients who underwent lobectomy showed longer survival than those who underwent pneumonectomy and other resection types (89, 27.5 and 65 months, P < 0.001). In summary, lung surgery is beneficial for patients with stage I-II non-small cell lung cancer as the second primary tumor after hormone-dependent malignancy resection.