Smokers are less likely to be alive and cancer-free three years after having
surgery for colon cancer than people who have never smoked, according to a new
Out of about 2 000 people who had part of their colon surgically removed,
researchers found 74% of those who had never smoked were cancer-free three years
later, compared to 70% of smokers.
Amanda Phipps, the study's lead author from the Fred Hutchinson Cancer
Research Center in Seattle, said the results provide another reason why people
should quit smoking. "It's nice when you have findings that portray a consistent
public health message," said Phipps.
According to the American Cancer Society (ACS), certain ingredients in
cigarettes can dissolve into a person's saliva and cause colon and other
The ACS estimates about 102 500 Americans will be diagnosed with colon and
rectal cancers in 2013, and over 40 000 will die from those diseases.
Phipps and her colleagues previously found smokers with colon cancer were
more likely to die than non-smokers from any cause and specifically from their
cancers. But the researchers wanted to take a closer look at what smoking meant
for colon cancer recurrence.
What the study found
For the new study, they analysed surveys that were given to about 2 000
people between 2004 and 2005 after they had colon cancer surgery but before they
received additional treatment.
Overall, 931 people said they had never smoked and 1 028 said they had smoked
at least 100 cigarettes during their lifetime.
Phipps and her colleagues found people who reported smoking were 23% more
likely to die or have their cancer return within three years, based on ongoing
surveillance of those patients. The difference was even more pronounced for the
140 people who said they were smoking at the time they were diagnosed with colon
They were 47% more likely to have a cancer recurrence or to die than people
who had never smoked.
"There is a difference. Certainly we see those current smokers have a poorer
prognosis," Phipps told Reuters Health.
The researchers found smoking was tied to worse outcomes in people with
tumours with certain genetic patterns but not others. Tumours that were positive
for so-called KRAS mutations, for example, came with a significantly worse
prognosis among smokers than non-smokers.
Overall, the researchers wrote in the Journal of Clinical Oncology that their
findings show "the effects of smoking may extend beyond an adverse impact on
colon cancer risk to also adversely impact outcomes after diagnosis."
The results only looked at outcomes over a short period of time, Phipps
She added that for people who continue to smoke, the health risks - such as
for heart disease and other cancers - will continue to accrue as times goes
"I would say as we get further and further away from a colon cancer
diagnosis, the impact from smoking is going to get greater," she said.