*3.1. Patient Characteristics*

The 37 patients recruited in this study (age range, 54–85 years; mean age, 70.5 ± 7.5 years) were divided into different groups according to the following characteristics (Supplementary Table S2): 31 males, 6 females; 30 smokers, 7 non-smokers; and pathological stage IA (n = 10), IB (n = 15), IIA (n = 2), IIB (n = 4), IIIA (n = 5) and IIIB (n = 1). The maximum tumor diameter ranged from 2 mm to 80 mm (mean tumor diameter, 24.5 ± 15.9 mm).

Twenty nine patients were diagnosed with double or triple primary lung cancers on the basis of histopathological characteristics, including 15 patients with adenocarcinoma–adenocarcinoma, 3 patients with squamous cell carcinoma–squamous cell carcinoma, 5 patients with adenocarcinoma– squamous cell carcinoma and 6 patients with other combinations. In terms of tumor development, tumors developed synchronously and metachronously in 26 and 11 patients, respectively. In patients with metachronous tumors, the tumors were designated as tumor 1 (T1), T2 and T3 in chronological order from the earliest to the latest. In those with synchronous tumors, this designation was based on the order of size from the largest to the smallest.
