In the fascinating book “The Tipping Point”, Malcolm
Gladwell describes how little things can cause big changes and how
these changes, once they start, can spread like an epidemic. New York City’s
crime rate had tripled in 10 years to an unbelievable 650,000 crimes per year
in the mid-1970s. It stayed steady at that rate until the early 1990s, when it
suddenly started to drop dramitically. 1992 was the tipping point. To get
there, the Broken Windows theory was put into practice. Minor, seemingly
insignificant crimes like fare-beating were cracked down on. Graffitti on
subway trains were cleaned immediately after the end of each ride and broken
windows on the street were repaired soon after stones were thrown. The context
in which crimes occurred started to change and the tipping point was reached.
It is what Malcolm Gladwell described as the Power of Context. I strongly
recommend this book to those who haven’t done so already.
In 1964, the Surgeon General issued the first report in
which tobacco was held responsible
for the 70% increase in the mortality rate of smokers over non-smokers. The
report estimated that smoking increased the risk of lung cancer 20-fold in heavy smokers. Since then, the incidence of
lung cancer and the number of deaths caused by it have increased as the
epidemic of smoking has continued to spread throughout the world. Only in the
last few years has there been a change in this trend in some countries, such as
the US, where incidence and mortality rates have droped ever so slightly. But
yearly lung cancer still kills more than 150,000 people in the US alone, and
more than 1.3 million people worldwide.
In 1980, the American Cancer Society (ACS) issued a
recommendation against screening for
lung cancer with chest-x-rays, the only technique available at the time to see
a cancer in the chest of a smoker. This recommendation was based on results of
3 large studies sponsored by the NCI in the 1970s.
For close to 40 years following that, millions of dollars have
been invested in research for effective treatments for advanced lung cancer,
and all official recommendations were against any efforts for screening. After
billions of dollars invested, today the chances of surviving 5 years after being
diagnosed with lung cancer are not better than 15%, exactly the same chances
you had 40 years ago.
However, over these years, there have been great advances in
screening for lung cancer that have brought us to what I think is the Tipping Point in lung cancer screening,
and probably in lung cancer as we know it. In 1999, results of a pivotal study
were published in LANCET, one of the
most prestigious medical journals. The Early Lung Cancer Action Program (ELCAP), lead by Dr. Claudia Henschke,
found that by doing a CT scan of the chest to smokers using low doses of
radiation, 85% of lung cancers could be detected in stage I, and most could be
cured with surgery.
Following this preliminary study with 1,000 volunteers, the
International ELCAP consortium (I-ELCAP)
was created in 2000 with the objective of screening tens of thousands of people
at risk for lung cancer using the same technique, and proving that a high rate
of cures could be achieved. In 2006, the I-ELCAP group published key results in
the New England Journal of Medicine
after screening more than 35,000 individuals in over 50 centers from around the
world. The results were so astonishing that the medical mainstream did not
accept them right away. In fact, many critics made themselves heard. In
summary, close to 500 lung cancers were diagnosed, again 85% of them in stage
I, and close to 90% of the patients were alive 10 years after the diagnosis.
This was unheard of in the field of cancer in general, and lung cancer in
particular.
In spite of clear evidence to the contrary, many critics
claimed that a large proportion of the 500 cancers diagnosed would not have
resulted in the death of the patient if they hadn’t been detected. This is a
bias in science known as overdiagnosis. So no official
medical assotiation made any changes in their negative recommendations, and
millions of patients with lung cancer continued to die every year. From 2006, year when these results were
published, it is estimated that more than 5 million people have died from lung
cancer in the world.
In August of 2011, another pivotal study was published. Due
to the doubts surrounding the ELCAP results, the NCI sponsored a large
randomized controlled study (NLST - National
Lung Screening Trial) to see if screening with low dose CT would reduce the
number of deaths from lung cancer. The difference between NLST and I-ELCAP is
that in the former there was a control group to which screening was not applied
with LDCT but with a chest-x-ray. I-ELCAP researcher believed that their study,
in which everyone was screened with a LDCT, could prove that screening could
cure a high proportion of cancers and that a control group was not necessary.
This is what caused all the controversy.
In november 2010, the NCI had to halt the NLST study ahead
of time because there had already been a reduction in mortality of over 20%,
which was the trial’s objective at the outset.
In January 2012, the NCCN (National Comprehensive Cancer Network), a group that gathers
experts from the top cancer centers in the world, issued the first
recommendation favoring lung cancer screening for individuals who smoke or who
have quit smoking. All of a sudden many associations are coming out with guidelines
recommending screening. Just to name a few, the American Lung Assotiation (ALA),
the International Association for the Study of Lung Cancer (IASLC), the
American Society of Clinical Oncology (ASCO), the American Thoracic Society
(ATS), the Amercian College of Chest Physicians (ACCP), have issued similar
positive recommedations in the past few weeks.
If one visits web pages from the top US medical centers, and
listens to former critics who now recommend screening, it is clear that the
tide is turning. Most importantly, insurance companies are starting to
seriously consider paying for screening, aware that by detecting lung cancer
early, the higher costs of treatment for advanced cancer can be avoided.
As one of the Principal Investigators of I-ELCAP, and as a
physician who deals with this disease on a daily basis, I am sure that we are
at the starting line of a revolutionary paradign shift. Ten years from now, a
low dose CT of the chest will be as familiar as a mammogram or a colonoscopy,
but as we now know, much more effective.
If you are a smoker or a former smoker, I suggest you
approach your doctor and ask about lung cancer screening. Being the most common
and deadliest form of cancer, by undergoing screening your chances of living a
long life will be signficantly improved. However, you should first consider
quiting the habit if you haven’t already done so.
