The etiology of cancer is only partly understood today, despite intensive research. Currently, cancer is thought to be the product of a multistep, multifactorial process. There are two theoretical ways in which psychosocial factors may play a role in the development and prognosis of lung cancer. First, certain complex behaviors may lead to increased carcinogen exposure. A well-studied example is smoking. There is increasing evidence that smoking behavior is acquired and influenced by psychologic factors such as control of arousal and mood, as well as social norms and values, eg, peer pressure. Pharmacologic, psychologic and social factors play an important role in the continuation of smoking. This is therefore considered an indirect psychosocial factor, as opposed to direct psychosocial factors, such as loss of a partner or job. The latter may lead to changes in the immune or endocrine systems via psychologic processes such as grief during bereavement. In this section, we summarize the extensive work that has been done on psychosocial risk factors in lung cancer, related to both indirect and direct effects. ventolin 100 mcg Indirect Psychosocial Effects
Lung cancer is the only major cancer site for which indirect psychosocial factors have been shown to play a dominant role in the etiology of the disease. Reviews of the association between smoking behavior and cancer have consistently concluded that 80 to 90 percent of lung cancer and about 30 percent of all cancer deaths are caused by smoking.