Are small lung nodules cancer?

Needs biospy: Small nodules can be cancer, but they would need to be biopsied. Many times, the nodules are just scars and not cancer. If you find nodules on a cat scan of your chest, depending on the size, they need to be followed to make sure they don't grow or look ominous enough to warrant a biopsy. What to do about nodules also depends on your risk for lung cancer, i.e., were/are you a smoker, etc.

Lung nodules: Are very common, and most (>95%) are not cancer. The larger the nodule, the greater the probability of cancer. Nodules in the 4-5 mm range are rarely lung cancer, and a nodule that is 25 mm in size (about an inch) is 50-50, and so on. These odds are affected by your age, and whether you smoked or not. Most nodules simply require long term follow up out to two years, with some exceptions.