Table 1.

Patient characteristics

	Number	Total (%)
Age (years)	60.5 [39–76]
gender
men	27	61.3
women	17	38.7
Never smokers	7	16
Current and former smokers	32	72.7
unknown	5
Histology
Adenocarcinoma	41	93
Squamous cell	3	7
Stage at diagnosis
I	6	13.7
II	4	9.1
III	9	20.4
IV	25	56.8
Average time between samples (months)
Synchronous	1.2 (n = 13)
métachronous	18 (n = 31)