Table 1: Patient characteristics of central and peripheral squamous cell carcinomas ( ).

Central ( )Peripheral ( ) value

Age
 Median7275
 Range58–8862–860.21
Sex
 Male1434
 Female110.53
Smoking
 BI index median9601000
 BI index range400–18800–20000.66
Stage I7200.37
Stage II5100.83
Stage III330.29
Stage IV00
Severe emphysema (HRCT)2170.02
Interstitial pneumonia (HRCT)5210.08