When a lung mass is seen on an xray it is usually followed up by a cat scan. The risk of a nodule being lung cancer is directly related to the size. There are 2 general types of lung cancer: Small cell lung cancer, which is usually a more aggressive cancer that spreads outside the lungs early. Non small cell lung cancer includes adenocarcinoma and squamous cell cancer have a better prognosis, and are less likely to have spread at the time of diagnosis. Univ. of Maryland.