Past long-term American Cancer Society follow-up studies have played a major role in cancer prevention at the American Cancer Society, as well as in other national and international efforts. More than 300 scientific articles by American Cancer Society epidemiologists have been published from these studies and findings have significantly contributed to tobacco-related research, and to the understanding of obesity, diet, physical activity, hormone use, air pollution, and various other exposures in relation to cancer and other diseases.

Past American Cancer Society long-term studies include:

Hammond-Horn Study (1952-1955): Included 188,000 U.S. men recruited by 22,000 volunteers. This study was the first large prospective study to examine the effect of cigarette smoking on death rates from cancer and other diseases. This study set the methodologic foundation for the two subsequent Cancer Prevention Studies (CPS-I and CPS-II).

Cancer Prevention Study (CPS)-I (1959-1972): CPS-I included approximately one million men and women recruited by 68,000 volunteers in 25 states. In contrast to the Hammond-Horn Study, CPS-I was designed to address a wide range of potential exposures, in addition to tobacco use, that may increase or decrease cancer risk.

Cancer Prevention Study (CPS)-II (1982-ongoing): CPS-II includes 1.2 million subjects recruited by 77,000 volunteers in 50 states, Washington, DC, and Puerto Rico. All participants have been followed for over 20 years to determine causes of death. Like CPS-I, this study was designed to address a wide range of environmental and lifestyle exposures that may increase or decrease cancer risk.

CPS-II Nutrition Cohort (1992-ongoing): 185,000 CPS-II participants from 21 states were enrolled in the new CPS-II Nutrition Cohort, a study designed to better understand how diet affects cancer risk. We periodically mail questionnaires to CPS-II Nutrition Cohort members to update exposure information and follow them for both cancer occurrence and all causes of death. For many members of the CPS-II Nutrition Cohort, biological specimens (blood and buccal (cheek) cells) have also been collected. The CPS-II Nutrition Cohort was designed to address a wide range of potential exposures, behavioral, environmental, and genetic, that may increase or decrease cancer risk.

Results from previous American Cancer Society long-term follow-up studies have demonstrated:

• The link between cigarette smoking and lung cancer
• The significant impact of being overweight or obese on risk of cancer occurrence and death
• The impact of hormones, physical activity, diet, various medications and vitamins, and various other factors in relation to cancer risk
• The impact of air pollution on cardiopulmonary conditions motivating the Environmental Protection Agency to propose more stringent limits on particulate air pollution
• the link between aspirin use and reduced risk of colon cancer
• the link between postmenopausal hormone replacement therapy and various gynecologic cancers (such as breast and ovarian cancer)
• the link between diabetes and cancers of the pancreas and colon
• the link between physical activity and lower risk of various cancers (including breast, colon, and aggressive prostate cancer)