Factors that increase the chance of developing cancer are
referred to as cancer risk factors. These factors directly
or indirectly increase the chance that a cell will acquire a
genetic mutation and therefore increase the chance that
a cell will become cancerous (see sidebar on Why Did I
Get This Cancer?, p. 19). Decades of research have led to
the identification of numerous cancer risk factors (see
Figure 3, p. 24) ( 27).
Many of the risk factors that have the biggest impact on
cancer incidence are avoidable (see Figure 3, p. 24). For
example, many cases of cancer could be prevented either
by individuals modifying their behaviors or through the
development and implementation of new public education
and policy initiatives that encourage individuals to avoid
cancer risk factors or protect people from cancer risk
factors in the workplace or environment. In fact, a recent
study suggests that between 40 percent and 60 percent of
cancer cases among white Americans could be prevented if
each person did not smoke, limited alcohol consumption,
maintained a healthy weight, and undertook regular
physical activity ( 29). These lifestyle behaviors also increase
risk for cancer in other U.S. racial and ethnic groups, but
the absolute contributions of these factors to cancer risk
in nonwhite populations remain to be determined.
Many cancer risk factors are also risk factors for other
chronic diseases, such as cardiovascular disease,
respiratory diseases, and diabetes. Therefore, reducing
or eliminating exposure to these factors through behavior
modification or public education and policy initiative
implementation has the potential to reduce the burden
of both cancer and other diseases.
In the United States, many of the greatest reductions
in cancer morbidity and mortality have been achieved
through the implementation of effective public education
and policy initiatives. For example, major public education
and policy initiatives to combat cigarette smoking have
been credited with preventing almost 800,000 deaths
from lung cancer from 1975 to 2000 ( 31). The researchers
concluded, however, that this figure represented just 32
percent of the lung cancer deaths that could have been
prevented during that period if tobacco control strategies
had completely eliminated cigarette smoking ( 31).
Clearly, a great deal more research and more resources are
needed to understand why some individuals continue to
engage in risky behaviors despite current public education
and policy initiatives, and how best to help these individuals
eliminate or reduce their risk of some cancers. One recent
• More than half of global cancer cases are a result of preventable causes.
• Not using tobacco is the single best way a person can prevent cancer from developing.
• About 20 percent of U.S. cancer diagnoses are related to people being overweight or obese,
being physically inactive, and/or consuming a poor diet.
• Many cases of skin cancer could be prevented by protecting the skin from
ultraviolet radiation from the sun and indoor tanning devices.
• The number of U.S. cancer cases attributable to human papillomavirus (HPV) infection
is rising, but most U.S. adolescents have not received the full HPV vaccine course.
• Exposure to environmental cancer risk factors remains a challenge for certain
segments of the U.S. population.
In this section you will learn:
of all global cancer cases
are preventable ( 30).