Instructor: Hi, everyone.
This will be the last video
in our lecture series about lung cancer,
and in this lecture we'll discuss survival and protection.
So we only have one goal in this presentation
and that is to describe
lung cancer prevention, control, and therapy.
So this figure from your textbook
shows the trend in five-year lung cancer survival,
and fortunately, we see that
the survival percentage has increased, albeit slightly,
from 1960 to 63 to 2004 to 2005,
and this is despite intensive medical efforts
involving surgical resection, chemotherapy,
and radiation therapy.
The primary reason for the failure
of treatment protocols to improve survival
is the lack of early detection of lung tumors.
Standard chest x-rays and most other imaging techniques
have shown little value in detecting lung tumors
prior to the invasion of the blood, lymphatic system,
contiguous tissues, and more distant sites of the body.
The imaging technique spiral computerized tomography
has been demonstrated to accurately identify
preneoplastic lesions of the lung in one center
but not others.
The primary prevention of lung cancer
depends to a large extent
on the prevention of cigarette smoking
among adolescents and young adults.
In the U.S., anti-smoking programs and laws
have led to reduced
prevalence rates of smoking in adolescents from 30% to 40%
to 20% to 25% in the U.S. over the past 20 years.
Despite international public health efforts,
a huge segment of the world population, nearly a third,
continues to smoke.
As a consequence of this addictive habit,
5.4 million people are dying annually
from tobacco-related diseases
like lung cancer, heart disease, and stroke,
chronic obstructive pulmonary disease
and other forms of cancer.
In 1988, British scientists reported the results
of a randomized prospective study
of daily aspirin use among 5,139 British physicians.
This study was designed to determine
if 500 milligrams of aspirin daily
would reduce rates of stroke, myocardial infraction,
and other conditions.
In this study, 3,429 of the enrolled subjects
were randomly assigned to receive aspirin
and 1,710 were randomly assigned
to avoid taking any aspirin or aspirin products.
After six years of follow up,
the observed death rate from lung cancer
was 7.4 per 10,000 person years
in the group treated with aspirin
and 11.6 per 10,000 person years in the control group,
meaning that there was a relative mortality of 0.64
in the group using aspirin compared to the group without.
Many subsequent investigations have also observed
significant protective effects of aspirin
and other NSAIDs against the development of lung cancer.
For example, an early case control study
of lung cancer and NSAIDs
observed a risk reduction of 60%
with the use of selective COX-2 inhibitors
and comparable risk reductions
with regular use of ibuprofen or aspirin.
Notably, the comparison group in the study
consisted of controls that smoked
but did not have lung cancer.
In a meta-analysis of 18 studies of lung cancer and NSAIDs,
the combined relative risk estimate
for regular NSAID users was 0.72
with no evidence of heterogeneity among studies.
We also see that smoking cessation
has major and immediate health benefits for men and women
regardless of all ages.
Though there's typically a small weight gain
with smoking cessation
with some adverse psychological impact,
the health benefits of smoking cessation
far exceed any risks.
On average, former smokers live longer
than continuing smokers,
and the benefits of quitting
extend to those who quit at older ages.
For example, persons who quit smoking before age 50
have one half the risk of dying in the next 15 years
compared to continuing smokers.
Furthermore, women who stop smoking before
or early during pregnancy
reduce their risk of having a low birth weight baby.
Smoking cessation reduces the risk of heart attack
and stroke by 50% within the first year after quitting
and rapidly improves pulmonary function in patients
with established chronic obstructive pulmonary disease.
Sustained smoking cessation produces a gradual decrease
in the risk of developing lung cancer
as well as other tobacco-related cancers.
Paradoxically, there is a slight increase
in the risk of lung cancer diagnosis
within the first few years after quitting smoking,
which is apparently related
to the modified growth characteristics
of existing lung tumors that enhances their detection.