Table 1

Study population features divided according to stage

Conventional risk factorsTotal%
Sex
    Male4282.3%
    Female917.7%
Smoker
    No611.7%
    Yes4588.3%
Surgical procedure
    Lobectomy3568.6%
    Pneumonectomy1631.4%
Histology
    Squamous2854.9%
    Non-squamous2345.1%
Grading
    G11121.5%
    G22243.1%
    G31835.4%