Most lung cancers arise from the epithelium of the airways and are classified as carcinomas. There are four major and several rare histological types of lung cancer. They appear to form through different mutagenic pathways; however, they all appear to undergo transition through a premalignant state. The presence of a transitional state from normal tissue to cancerous tissue is important because the premalignant cells contain damage that is generally thought to be reversible. Researchers are currently trying to develop methods to identify people with premalignant lesions as well as drugs that can reverse the damage.

Continued damage to premalignant cells can lead to cancer. The first appearance of cancer cells that have not yet become invasive is referred to as carcinoma in situ. Patients are rarely diagnosed with this early stage of cancer owing to a lack of symptoms and relatively rapid progression from this state to larger invasive tumors. As the tumor grows, cells may become dislodged from the tumor bulk and enter the hemato-logic or lymphatic circulatory systems where they can travel to either local or distant parts of the body. Hematologic spread usually results in metastatic sites in the bones, liver, and CNS. Lymphatic spread is more orderly in nature, with the hilar and mediastinal lymph nodes in the pleural cavity commonly being involved. Once the tumor has spread to multiple locations, curative treatment is rare because surgical excision and radiotherapy cannot remove all or nearly all the cancer cells.

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

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