Download An Ounce of Prevention

An Ounce of Prevention
From Scientific American September 1994
by Devra Lee Davis and Harold P. Freeman
1
Public hopes and presidential promises that cancer could be cured provided
much of the cultural meaning and all of the federal funding for the modern war on
cancer, launched some two decades ago. The search for a cancer cure, in part,
reflected the belief that the disease arises chiefly from discrete external entities such as
viruses that can be attacked and eradicated.
2
Lately the war on cancer has reinvented itself as the exhilarating quest for
defective genes. We read and hear that all cancer is genetic in origin, arising from
mutations in the basic building blocks of cells that lead to unregulated growth. Yet only a
relatively small portion of most dominant types of cancer is inherited. The key questions
remain: What causes the majority of people who have originally inherited a healthy
array of genes - some 95 percent of women with breast cancer, for instance – to
develop defects that lead them to acquire cancer; and what strategies can be applied to
reducing the incidence of disease for all segments of society?
3
The history of infectious disease in the 19th century supplies a model. Such
illness began to decline as a major cause of death largely because of improvements in
providing cleaner water, food and air and better housing and working conditions.
Reductions in the number of people suffering from these diseases usually stemmed not
from treatment but from public health programs that kept these afflictions from occurring
in the first place.
QUESTIONS
1. Which two possible causes of cancer have already been explored by scientists
in the past?
i) __________________________________________
ii)__________________________________________
10 pts
2. Why do the writers cite the statistics on breast cancer in paragraph 2?
They want to refute the scientific claim that
________________________________
___________________________________________________.
10 pts
3. Why is the history of infectious disease in the nineteenth century mentioned in
paragraph 3?
a) It provides a model for techniques for tracing disease
b) It provides a model for methods for early detection
c) It provides a model for strategies for treatment
d) It provides a model for programs for prevention
10 pts
4
Of course, there are more cases of cancer today because there are more older
people, and the technology for identifying the disease has advanced. But the rate of all
new cases of cancer, excluding that of the lung, has increased about 35 percent
since1591; by one estimate, rates of cases not linked to smoking have tripled in men of
the baby-boom generation and grown by a third in women of that generation, compared
with their great-grandparents.
9
In most modern countries, one individual in three will contract some form of
cancer, and one in four will die from it. Rates of breast cancer, multiple myeloma and
brain cancer have been rising for several decades and are about five times higher in the
U. S. than in some Pacific Rim countries and up to 50 times higher than in less
developed countries. This remarkable divergence in cancer patterns within and between
geographic regions, along with elevated rates in some poor, disadvantaged
communities and notably high incidences in about 50 different workforces, implies that a
substantial segment of cancer is avoidable or postponable.
6
At present, the mounting toll of lung cancer provides incontrovertible evidence
that smoking remains the single most important avoidable cause of cancer, responsible
for about 30 percent of all cancer deaths in industrialized societies. But a prolonged and
protracted scientific debate greeted first reports in 1949 from Ernst Wynder that tied
smoking to lung cancer. While this debate persisted, millions of people became
addicted. Recent reductions in lung cancer in white males in the U. S. and several other
developed countries constitute a bona fide public success, largely attributable to a
decline in the number of those who smoke. Unfortunately, smoking-related lung cancer
continues to increase at alarming rates in women in those countries. Also lung cancer in
nonsmokers has reportedly increased in several countries.
4. (para 5 ) We can infer that the “remarkable divergence in cancer patterns” is a
result of
a) poverty and economic disadvantage
b) certain geographical conditions
c) industrialization and modernization
d) changes in world health patterns
8 pts
5. a) When Ersnt Wynder first published research linking cancer to smoking, how
did people react?
Because his findings were accepted / not accepted immediately, people
continued to smoke / stopped smoking. (circle the correct option in each
case)
6 pts
b) Whereas lung cancer in women in Western countries has
__________________, in men it has ________________.
6 pts
7
A growing body of experimental and human evidence has identified a number of
significant environmental risk factors as causes of cancer. They include past diagnostic
and therapeutic radiation; diets high in some fats and low in fresh fruits and vegetables;
workplace exposures to chemicals, dust and fumes; pharmaceuticals; sunlight; and
heavy alcohol drinking. Long-term, low-level exposures to some environmental
contaminants, such as small particulates, chlorination by-products in domestic water
and organochlorine residues in animal and fish fat, appear to increase the risk of cancer
in human populations, and extensive animal studies indicate a clear risk. Some
compounds may function by alerting hormones, whereas others may directly affect gene
expression.
8 Meanwhile two decades and $24 billion since the formal launching of the war on
cancer, both the war and its warriors are weary. Despite some stunning and gratifying
successes in curing the relatively rare cancers of young people, no radically different
intervention has been developed for any of the predominant forms of the disease. The
poor and uninsured have limited access to early detection and treatment and are often
first diagnosed with much higher rates of advanced illness. Even where treatment for
relatively rare cancers has been effective, as with testicular cancer, new cases have
more than doubled in the past two decades in many countries. Moreover, cancer-cured
children and young adults sometimes face a troubling legacy: they have been subject to
intensive radiation, surgery or chemical treatments at vulnerable stages of their lives
and carry lifelong increases in risk and reductions in function.
6. Why are dust and fumes, heavy alcohol drinking and sunlight mentioned in
paragraph 7?
________________________________________________________________
10 pts
7. On the whole, do the writers consider the war on cancer a success?
Yes / No
(circle one)
Copy a statement from the text to support your answer
___________________________________________________________ 10 pts
5
This country spends about five times more per patient on chemotherapy than the
U.K. does, but survival for most common cancers does not differ. Even when benefit is
unexpected, chemotherapy and other cancer treatments have come to be regarded as
an entitlement. A decade ago John Cairns of Harvard University pointed out the folly of
pouring hundreds of millions of dollars every year into giving a growing number; of
patients chemotherapy with little proven benefit for the major types of cancer, while
doing virtually nothing to protect the population from cigarettes. To this sensible charge,
we now wish to add that it is time to turn attention to confirming other avoidable causes
of cancer.
10
No matter how efficient we may become at delivering health care, we must also
seek to reduce the need for treatment. An increase in cases of cancer in younger
persons in the U. S. and parallel findings in Sweden indicate that we need to identify
avoidable causes of cancer in addition to smoking and to develop effective interventions
that keep people from developing the disease altogether. If we avert only 20 percent of
all cancers each year, we will save more than 200,000 people and their families from
this difficult disease and spare the public from the burgeoning costs of treatment and
care.
QUESTIONS
8. According to paragraph 9, people accept chemotherapy and other cancer
treatments as their right. What is the authors’ opinion of this view?
They agree / disagree (circle one)
Justify your answer:
_______________________________________________________
______________________________________________________.
10 pts
9. The main idea of this article is:
a. Funding should also be allocated to explore possible preventive causes of
cancer.
b. It is better to spend the funding on providing better health care for cancer
patients.
c. It is a complete waste of money to spend funding on expensive treatments.
d. Funding should be used to reduce rates of smoking-related lung cancer.
10 pts
10. If the government were preparing a budget for the war on cancer, which one
of the following proposals would the writers probably support?
a) Increased research on environmental factors which add to the risk of
cancer
b) Increased funds for chemotherapy treatment for poor and uninsured
patients
c) Increased funds for research on the link between smoking and cancer
d) Increased research on new methods of intervention for advanced stages
of the disease
10 pts