In many respects, cancer is a preventable disease. Estimates indicate that approximately one half of all cancer cases either arise from modifiable risk factors or can be detected as precursor lesions before the development of disease with metastatic potential.
Prevention of cancer can take place on several different levels:
Primary prevention addresses the cause of cancer, so disease does not occur
Secondary prevention identifies disease before the onset of symptoms and keeps it from becoming more extensive
Tertiary prevention reduces complications and progression of disease once it has become clinically apparent
Although cancer has overtaken cardiovascular disease to become the leading cause of death in men and women younger than 85 years in the United States, and the number of cancer deaths continues to increase with the aging and growth of the population, age-standardized US death rates from cancer have been decreasing.
The US cancer death rate peaked at 215.1 per 100,000 population in 1991 and declined to 166.4 per 100,000 population in 2012. The overall incidence rate of cancer in women has remained stable since 1998, but in men it has declined by 3.1% per year since 2009.
These declines have been attributed to risk reduction strategies, detection of early disease, and improvement in treatment strategies. This review addresses the first 2 of those factors, to summarize the evidence for prevention in oncology.