HOLLYWOOD, Florida-Smoking not only increases the
risk of developing pancreatic cancer but also speeds disease progression,
according to Randall E. Brand, MD. In a presentation at the 2005
Gastrointestinal Cancers Symposium (abstract 76), Dr. Brand said that current
smokers develop pancreatic cancers about 10 years sooner than nonsmokers.
"Smoking at any age has an impact on the age of diagnosis of pancreatic
cancer," Dr. Brand said. "To our knowledge, this is the first report that
provides compelling evidence for the role of cigarette smoking early in
neoplastic transformation of the pancreas."
Previous studies had estimated that about 25% of pancreatic
cancer cases are strongly associated with smoking, which is "the most
significant and reproducible environmental risk factor" associated with this
cancer type, Dr. Brand said. In the United States, there are more than 30,000
new cases of pancreatic cancer diagnosed each year, and most patients die
within the first year after diagnosis.
Dr. Brand and his colleagues at Northwestern University’s
Feinberg School of Medicine used data from the Cancer Information Resource File
(CIRF) to examine the impact of smoking on the age of diagnosis of pancreatic
cancer. The CIRF includes data from more than 350 teaching and community
hospitals. The investigators identified 18,346 pancreatic cancer patients with
available smoking histories. Dr. Brand said that demographically, these
patients resembled the general population: 52% were males, 86% white, 12%
black.
The analysis showed that pancreatic cancer patients who were
current smokers were diagnosed about 10 years younger than those who were never
smokers (age 63 vs 73, P < .001). "Smoking appears to accelerate the
onset of pancreatic cancer development," Dr. Brand said. Previous smokers were
diagnosed at a median age of 70. The smoking-related accelerated progression
was found in all cancer stages.
Stopping Smoking
Interestingly, stopping smoking eventually reversed this
effect in men but had less impact in women. Dr. Brand reported that men who had
stopped smoking were not younger than male never smokers at the time of
pancreatic cancer diagnosis (age 70 for both). Females who stopped smoking
developed pancreatic cancer later than current smokers (age 71 vs 65) but did
not revert back to the same age of diagnosis as a never smoker (74), Dr. Brand
said. He told ONI that it would be interesting to compare the effect of
stopping smoking in premenopausal vs postmenopausal women, but those data are
not available in this database.
Initiation and Progression
"Our analysis strongly suggests that smoking may augment
both the initiation and the progression phases of pancreatic cancer
carcinogenesis," Dr. Brand said. "The age of diagnosis of previous smokers is
younger than nonsmokers, suggesting that smoking augments the initiation phase.
The age of diagnosis of current smokers is younger than previous smokers and
never smokers, indicating that smoking augments the progression phase."
Dr. Brand emphasized that "to stem the tide of increasing
pancreatic cancer deaths and reduce the additional years of lost life due to
the earlier diagnosis" is likely to require not only helping current smokers
quit but preventing never smokers from beginning to smoke.
The mechanism underlying the effect of smoking on the pancreas is uncertain.
Dr. Brand said that researchers had suspected that carcinogens derived from
tobacco smoke might become concentrated in the bile, but "preliminary data do
not support that."