Although most lung nodules have no cancer, some of them can be cancerous, according to Mayo Clinic. Typically, lung nodules measure 5 to 30 millimeters in size. Lung nodules that measure over 30 millimeters are more susceptible to cancer than smaller ones.
Lung nodules are tissue deposits in the lungs, says Mayo Clinic. They are round-shaped shadows when observed through x-rays or computerized tomography scans. When they change in shape, appearance and size over time, they may be cancerous. Although no treatment is necessary for noncancerous lung nodules, they should be regularly checked for change to determine their cancer status.