More than half a million people died from cancer in the U.S. in
2011. We have many astounding advances in medicine to thank for
that number not being higher. But that grim
figure could also be a lot lower even without a breakthrough drug
for breast or lung cancer.
In fact, more than 280,000 of those lives could have been spared
by preventing the disease in the first place—all
via behavioral and research changes based on scientific discoveries
that have been made already, according to a new review article
published online March 28 in Science Translational
Medicine. This statistic is not new, the researchers pointed
out, but quibbling over details of exactly how many cases of—or
deaths from—each form of cancer are due to preventable risk factors, the researchers
noted, has delayed investment in mitigating the risks that
researchers already know about, the authors argued.
“We actually have an enormous amount of data about the causes
and preventability of cancer,” Graham Colditz, a professor at the
Washington University School of Medicine in St. Louis and co-author
of the new study, said in a prepared statement. “It’s time we made
an investment in implementing what we know.”
Scientists know, for instance, that more exercise and less
alcohol intake can lower the risk for breast cancer and that
quitting smoking drastically reduces the risk for lung cancer. We
also know that vaccines for HPV and hepatitis can reduce liver and
cervical cancers by more than half and that aspirin can reduce
overall cancer death by some 20 percent. Getting these
interventions to the right people, however, is easier said than
done.
“The obstacles to these efforts are societal and arise from the
organization of institutions, including academia, and in the habits
of daily life,” the researchers wrote.
And habits can be hard to break, especially the biggest
cancer-causing habit of all: smoking. Without smoking, at least 75
percent of all lung cancer cases in the U.S. could be avoided, they
noted.
Research, too, needs to change the ways it gets things done.
With the lion’s share of funding for cancer research allocated to
seeking new treatments, the science of prevention can get short
shrift—in funding and in academic esteem. Although much progress
has been made in developing treatments to extend the lives of those
who already have specific kinds of cancer, the researchers
suggested that “behavioral interventions, such as smoking cessation
or promotion of physical activity can diminish incidence and
mortality of many types of cancer and other chronic diseases
while at the same time improving quality of life.”
Colditz and his colleagues suggested that professional prestige
be bestowed not just on basic biological discoveries, but also on
applied medicine and those who discover how to make the best use of
what we already know. “There is much more the United States and the
world and be doing to prevent cancer. Right now,” they wrote.
Perhaps one the biggest hurdles in putting prevention to work,
however, has been our own rush to see results. “Humans are
impatient, and that human trait itself is an obstacle to cancer
prevention,” they noted. “Studies that focus on short-term
exposures or short-term follow-up almost certainly will miss the
true benefits of prevention.”
For example, despite reductions to the amount of asbestos
workers could be exposed to starting in the 1970s in the UK, rules
were slow to be fully implemented and extended to lower levels of
exposure. So, asbestos-related cancers will probably keep rising
there until 2020. Likewise, on an individual level, someone who
quits smoking drops his or her risk of lung cancer by 13 percent in the first
five years after stopping. Not bad, but by 10 years out, the
risk drops by 33 percent.
So to really prevent more cancers over the long haul,
researchers and policy makers should take the long
view—interventions and study participants should be followed not
for two or five years, the researchers noted, but for 20 and
beyond. And these studies should start earlier. Many cancers take
decades to develop, and even lifestyle choices made in our youth,
such as alcohol use and lack of physical activity, can impact
cancer risk down the road. So to realize the biggest results, the
authors noted, “studies and interventions should be targeted at the
early stages of the human life span, but this rarely happens.”
Colditz and his colleagues also argued that achieving dramatic
cuts to cancer incidence requires immediate action—individually and
collectively. “Each passing year leaves a substantially greater
portion of the world population at risk for cancer, despite our
current knowledge,” they wrote. “We have a moral responsibility to
act now and reduce that burden.”