Patient selection
NSCLC, non-small-cell carcinoma, tumor, Tumor, pulmonary metastasis, adenocarcinoma, primary lung cancer
NON-SMALL CELL LUNG CANCER, TUMOR, LUNG, TUMOR, PULMONARY METASTASIS, ADENOCARCINOMA, NSCLC, SQUAMOUS CELL CARCINOMA, LARGE CELL CARCINOMA
The inclusion criteria were: (1) primary lung cancer; (2) tumor descriptor with ipsilateral pulmonary metastasis [based on Separate Tumor Nodules Ipsilateral Lung Recode (2010 +) with the information of separate nodules of the same hist type in the ipsilateral lung, same or different lobe]; (3) no overlapping primary sites; (4) histological confirmation of adenocarcinoma (histologic codes 8244, 8245, 8250–8255, 8260, 8290, 8310, 8323, 8333, 8480, 8481, 8490, 8507, 8550, 8570, 8571, 8574, and 8576), squamous cell carcinoma (histologic codes 8052, 8070–8075, 8083, 8084, 8123), large cell carcinoma (histologic codes 8012–8014), and other non-small-cell carcinoma (8046, 8050, 8003,8004, 8022, 8031–8035, 8082, 8200, 8240, 8249, 8430, 8560, 8562, 8980); (6) history of surgery (sublobectomy, lobectomy or pneumonectomy); and (7) survival time should be at least one month.The exclusion criteria were: (1) unknown tumor location and laterality; (2) without any treatment; and (4) incomplete demographic data. More details of the data extraction process are presented in Fig. Flow diagram of the data extraction process. SEER, the Surveillance, Epidemiology, and End Results; NSCLC, non-small cell lung cancer; IPM, ipsilateral pulmonary metastasis