Lung cancers grow at different rates depending upon the intrinsic properties of the cancer. It is true that most lung cancers are actually detected very late in their course. This happens because lung cancer often has no symptoms and requires significant growth of the tumor or impingement of the tumor upon other organs to create symptoms.
Lung cancer is usually divided into two broad categories, small cell cancer and non-small cell cancer. Small cell lung cancer is notorious for growing extremely fast with death often occurring within 6 months when no treatment is received. This rapid growth, however, makes this type of cancer susceptible to chemotherapy drugs. Lung cancers sometimes grow extremely slowly. In fact, when a doctor finds a nodule (a rounded density) on a chest x-ray, unless it has certain characteristics (like calcium deposits), it must be observed and followed for two years before the doctor can say that it is benign (non-cancerous).
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