Tumors at this stage are small in size. There is no spread to lymph nodes or other organs. Stage I is further divided into stages IA and IB based on tumor size. Small tumors, i.e., those up to three centimeters (3 cm) in greatest dimension, are Stage IA, while slightly larger ones – i.e., from 3 cm up to 4 cm in greatest dimension – are Stage IB. Tumors at this stage are surrounded by lung parenchyma or visceral pleura (the lining of the lung). Most of the time, they are asymptomatic.