Depending on how much they
smoke, cigarette smokers are 5 to 17 times more likely to die from lung cancer
that are non-smokers—a fact most of the will readily acknowledge. But while admitting that cigarettes cause cancer,
these same smokers nevertheless refuse to give them up, reasoning that the
harm, if any, has already been done.
“If I’m marked for lung cancer,” runs their argument, “It’s too late to
do anything about it. Why stop now?”
Why, indeed? For years there was a certain irrefutable
logic to this argument. Cancer of the
lung is a silent invader, one that usually grows to lethal dimensions before
signaling its presence. Thus, despite
the most skilled treatment, the rescue rate is still dismally low; of the total
number diagnosed, only 5 percent are cured.
So why stop? Why give up a habit
you’ve grown to love?
It seems a comforting, warm,
smug kind of justification. But it no
longer holds water. Indeed, today there
is good reason to believe that a period occurs early in the life history of lung
cancer when the ore-cancerous cells actually require a continuous supply of the
cancer producing irritant—tobacco smoke, in this instance—to survive and
grow. If this supply is turned off and
kept off for five years or more, the potentially lethal cells will shrivel up
and disappear.
This fundamental and rather
startling discovery came during a 13-year study conducted in my laboratory at
the Veterans Administration Hospital in East Orange, New Jersey. My colleagues in the study were Dr. E. Cuyler
Hammond and Lawrence Garfinkel, then have the American Cancer Society’s
statistical department. What we were
looking for when we launched the project were very early changes that might
signal the beginning of cancer in the bronchial epithelium, the lining of the
branching air passages within the lungs, where cancer is often known to
arise. We could not, of course, witness
these changes in a living person, for they occur deep within the lung. Our information has come, therefore, from
studies of more than 100,000 paper-thin silvers of lung tissue, taken at
autopsy from over 1200 men and women, ranging in age from 22 to 84, who had
died from heart disease, brain tumor, phumonia, accidents and other causes
including, of course, lung cancer.
Among them were light, moderate, heavy and non-smokers, and ex-smokers.
During one of these studies,
as we examined sections from smoker’s lungs, we noted that many changes in the
cell pattern of the bronchial lining had taken place, in a gradual
evolution. In effect, we were observing
the step-by-step transformation of normal cells into cancer cells. And the frequency of abnormal cells closely
paralleled the number of cigarettes the person had smoked during his life. But in many of the slides we noticed that
the membrane that separates these cells from the underlying supporting tissue
was still intact, holding the mest of potential troublemakers in place—and thus
preventing their escape into the blood vessels which would spread them to other
areas. We classified this stage of
development as “cancer in situ,” which simply designates a cluster of tumor
cells still lying within the bronchial lining where they originated.
As long as cells remain
quietly in situ they do no harm. But
they still carry the malignant potential.
And the next step in their life history is penetration of the basement
membrane. When this happens the tumor
has reached the point of no return, invasive cancer has begun.
At this point, to see what
actually does happen inside a habitual smoker’s lung after he stops saturating
it with tobacco smoke, we set up comparative study of three 72-man groups. Those in one group had smoked most of their
lives, to the time of death. The second
group was lifelong abstainers. The
third consisted of men who had smoked ten years or more and had given up it at
least five years. All had died of
causes other than lung cancer.
To assure that we would not
be influenced in our search for cancer cells by foreknowledge of a person’s
smoking habits, the lung sections in each group came to our laboratory
identified only by serial number. But
after we had finished our examination of some 10,000 slides, and our reports
were linked up with individual case histories, we saw at once how finitely the
cessatio of smoking was reflected in the condition of the bronchial
lining. Cancer in situ, that last stage
before invasive cancer, appeared 40 times as often in the smokers as in those
who had quit. (No cancer in situ was
seen in any of the non-smokers.) In
many instances, the bronchial linings of the ex-smokers were healthy-looking as
a child’s. Yet the odds are
overwhelming that these same lung linings at one time harbored numerous
pre-cancerous lesions—lesions that had disappeared without a trace after the
individuals stopped smoking.
Well, not quiet without a
trace. As I was porting over the
thousands of slides I was struck by the appearance here and there of
odd-looking cells of a type I had never seen before. The cell nuclei were contracted, crescent-shaped or just
shriveled, and sometimes had left a clear halo around them as they shrank. At first, I simply made the notation,
“Unusual finding in epithelium,” and told associates what I had seen. They checked the origin of each strange
slide; then, while keeping that information from me, they asked me to
re-examine the first thousand slides.
Eventually, I found the
disintegrating nuclei in 518 sections—and it turned out that every single one
had come from the lung of an ex-smoker.
We never saw a disintegrating nucleus in the tissues of either a heavy,
continuing smoker, of in a person who had never smoked.
The implication was
clear. What we were viewing was the
death and disintegration of pre-cancerous cells. And it seemed statistically beyond doubt that the process was the
direct result of the removal of the irritant, which had induced the abnormal
development in the first place—the tobacco smoke.
Although we have no way of
knowing just how much time elapses after the flow of tobacco smoke is turned
off before this self-repair process begins, our studies indicate it will take
place in a high percentage of smokers who stop smoking for five years of more.
Today, fortunately, many
smokers are giving the disintegration process a chance. The U.S. Public Health Service reports that
since 1957 there has been a significant decline in the number of people who
smoke. The American Cancer Society’s
statustucsm based on a massive survey of the smoking or non smoking habits of
the million American men and women, suggest that the longer you stay off
cigarettes the more closely your life expectancy and general health will
approach the levels of those who have never smoked. In fact, after ten years of no smoking, the death rates of
ex-smokers and lifelong abstainers are virtually the same.
Why stop now?
The answer is crystal clear.
