Population-Based Lung Cancer Prevention: An Overview

Lung cancer remains the leading cause of cancer-related mortality
in the United States, with 160,390 deaths projected for
2007. 1 Lung cancer accounts for the largest number of cancer
deaths worldwide as well, with an estimated 1.3 million deaths
in 2005. 2 These dismal numbers reflect persistent national and
global challenges to lung cancer control.
Cancer control in general relies upon prevention, early detection,
and treatment. Advances in the treatment of lung cancer,
including minimally invasive surgery and targeted molecular
therapies, have a limited impact on the burden of lung cancer
because of the fact that most cancers continue to be diagnosed
at an advanced stage. The presence of symptoms at the time
of diagnosis is associated with a high probability of advanced
disease. The failure of screening with chest radiography and sputum
cytopathology to impact lung cancer mortality suggests that
detection of asymptomatic disease is necessary but not sufficient
to achieve this goal. A resurgence of interest in early detection
has followed the widespread availability of chest computed tomography
(CT). Although this technology has proven superior
to chest radiography in detecting early stage lung cancers, a beneficial
effect on lung cancer mortality remains to be proven. 3
Smoking control programs continue to represent the most logical
approach to curtailing lung cancer incidence, but economic
and political forces oppose such efforts. 1 Reducing smoking
prevalence decreases an individual smoker’s risk of lung cancer as
well as that of others through a reduction in secondhand smoke
exposure. Unfortunately, an elevated risk of lung cancer persists
for many years after smoking cessation. 4,5 This risk is highest
among individuals who have undergone a curative resection for
lung cancer, who have a 1% to 5% annual risk of developing a
second primary lung cancer. 6 Chemoprevention has been studied
as a mechanism to decrease lung cancer risk in these highrisk
groups as well as in the general population.
A population-based approach to lung cancer prevention
will be required to achieve the greatest reduction in lung cancer
mortality, as many individuals lack access to the healthcare system
and may not otherwise be aware of their lung cancer risk.
High-risk individuals must therefore be actively selected from
the general population to ensure that the majority has the opportunity
to receive appropriate preventive measures. Investigators
have used such an approach to identify and recruit subjects into
an ongoing chest CT screening trial, 7 and we have previously
reviewed the criteria for a population-based approach to early
lung cancer detection. 8 In contrast to breast or colon cancer,
where the major defining risk factor is age, the profound risk associated
with tobacco use allows for a powerful and economical
additional selection factor to enrich for lung cancer risk. Other
risk factors of lung cancer exist, however, and these collectively
account for about 10% of lung cancer diagnoses. Which preventive
measures should be applied to which specific subgroups
of the population are questions that ongoing studies will help
to address, but the answers will likely be dynamic as novel approaches
are developed. This chapter will review contemporary
lung cancer prevention strategies with a focus on their potential
for implementation at a population level.