Note: A separate PDQ summary on Levels of Evidence for Cancer Screening and Prevention Studies is also available.
The cancer prevention summaries in PDQ refer to cancer prevention, defined as a reduction in the incidence of cancer. The PDQ includes summaries generally classified by histological type of cancer, especially when there are known risk factors for the specific types of cancer. This summary addresses a specific risk factor, tobacco use, which is associated with a large number of different cancers (and other chronic diseases) and unequivocally contains human carcinogens. The focus of this summary is on clinical interventions by health professionals that decrease the use of tobacco.
Childhood astrocytoma is a disease in which benign (noncancer) or malignant (cancer) cells form in the tissues of the brain.
Astrocytomas are tumors that start in star-shaped brain cells called astrocytes. An astrocyte is a type of glial cell. Glial cells hold nerve cells in place, bring food and oxygen to them, and help protect them from disease, such as infection. Gliomas are tumors that form from glial cells. An astrocytoma is a type of glioma.
Astrocytoma is the most common type of glioma...
Study Design: Evidence obtained from a randomized controlled trial.
Internal Validity: Good.
Magnitude of Effects on Health Outcomes: The relative risk (RR) of several cancers is much greater in cigarette smokers compared with nonsmokers (depending on the anatomical site of the cancer and the intensity and duration of smoking, the RR can range from twofold to tenfold or greater in smoking populations). A reduction of 15% is seen in the RR of all-cause mortality in heavy smokers subjected to intensive clinical cessation interventions.