Long-term, Heavy Smoking Doubles The Risk Of More Aggressive Prostate
Cancer In Middle-aged Men

SEATTLE - Middle-aged men who are long-term, heavy smokers face twice
the risk of developing more aggressive forms of prostate cancer than men
who have never smoked, according to new findings from Fred Hutchinson
Cancer Research Center that appears in the July issue of Cancer
Epidemiology, Biomarkers and Prevention, a publication of the American
Association for Cancer Research.

Specifically, men under age 65 with a history of 40 or more "pack-years"
(those who smoke a pack a day for 40 years or two packs a day for 20
years) of cigarette smoking face a 100 percent increased risk - or
double the risk - of developing more aggressive forms of the disease as
compared to nonsmokers, according to senior author Janet L. Stanford,
Ph.D., and colleagues in Fred Hutchinson's Public Health Sciences
Division. Such men with heavy smoking exposure also face a 60 percent
increased risk of prostate cancer overall relative to nonsmokers.
Compared to nonsmokers, current smokers experienced a 40 percent
increase in the risk of prostate cancer.

Researchers from the University of Washington School of Medicine also
collaborated on the study, which was funded by the National Cancer
Institute.
"This study provides additional evidence that supports a role for
smoking as a risk factor for prostate cancer and confirms recent
findings that suggest smoking is an even stronger risk factor for more
life-threatening forms of prostate cancer," said Stanford, director of
Fred Hutchinson's Prostate Cancer Research Program.

Previously, research results regarding smoking and prostate cancer have
been mixed, but these results, together with recent findings from
investigators at Johns Hopkins University and Harvard University,
provide cumulative evidence that smoking - in particular high-dose,
long-term cigarette exposure - is an important risk factor for prostate
cancer, said Stanford, also a professor of epidemiology at the
University of Washington School of Public Health and Community Medicine.

"From a public-health perspective, I think we now have enough evidence
to suggest that prostate cancer should be added to the long list of
malignancies in which smoking plays a role," she said. Other
smoking-related cancers include those of the lung, bladder, cervix,
esophagus and kidney.

The study involved more than 1,450 Seattle-area men, ages 40 to 64. Half
had a history of prostate cancer (diagnosed between 1993 and 1996) and
the other half, which did not have a history of prostate cancer, served
as a comparison group. Participants completed detailed in-person
interviews that assessed a variety of factors, from smoking and alcohol
consumption to diet and occupational history.

One of the study's strengths is that it focused on younger men who have
a lower overall incidence of prostate cancer, which may have enhanced
the researchers' ability to tease out the effects of specific risk
factors.

"The contribution of smoking to prostate cancer may have been easier to
detect in men under 65, who are at lower absolute risk of the disease,
than in older men, in whom the cumulative effects of numerous risk
factors may cloud the picture," Stanford said.

Another strength of the study is that it assessed other lifestyle
variables - from prostate-cancer screening history to dietary intake -
factors which, if unaccounted for during data analysis, might have
biased the results.
Smoking may promote prostate cancer through several mechanisms. One is
that it can increase the amount of circulating androgens, which fuel the
growth of normal and malignant prostate cells.
"Cigarette smoking appears to alter a man's hormonal milieu by tilting
the scale toward a hormonal environment that may be conducive to tumor
growth," Stanford said.

Another theory is related to tobacco as a source of cadmium, a heavy
metal that has been linked to prostate cancer in several
occupational-health studies. This known human carcinogen inhibits DNA
repair, which allows cancer cells to mutate and multiply.

"Cadmium has been shown to be concentrated in the prostate, so this may
be one chemical exposure from cigarette smoking that could have an
adverse biological effect on the prostate," Stanford said.

One positive finding, however, is that while the relative risk of
developing prostate cancer increases with the number of pack-years
smoked, this risk declines to near that of nonsmokers within about 10
years of quitting, Stanford said.
"When men stop smoking, within a decade their risk of prostate cancer
returns to a level that is not substantially different from nonsmokers,
so for most men, it's not too late to quit. There are few environmental
risk factors for prostate cancer that have been identified, but here's
one way that men can take action to reduce their risk," she said.
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SIDEBAR
IN ADDITION TO NOT SMOKING, WHAT ELSE CAN A MAN DO TO REDUCE HIS RISK OF
PROSTATE CANCER?
In addition to not smoking, what else can a man do to reduce his risk of
prostate cancer? Janet Stanford, Ph.D., director of the Prostate Cancer
Research Program at Fred Hutchinson Cancer Research Center, suggests the
following lifestyle changes based on research conducted at Fred
Hutchinson and elsewhere:
* Eat more vegetables. Vegetables contain phytochemicals, which can
boost the activity of enzymes that detoxify cancer-promoting compounds
in the body. A Fred Hutchinson study found that men who eat just three
servings of vegetables a day reduce their risk of prostate cancer by
about 45 percent. If some of these vegetables are from the cruciferous
family, such as cabbage, broccoli and cauliflower, the risk is reduced
even further.
* Reduce fat intake. A Fred Hutchinson study found that men who ate
lower-fat diets, with fat accounting for no more than 30 percent of
their daily calorie intake, had half the risk of more advanced stage
prostate cancer than men who consumed more fat.
* Eat more tomatoes. Lycopene, a nutrient that gives tomatoes their red
color, has been found in some studies to reduce prostate-cancer risk.
Cooking the tomatoes with a bit of olive oil, as in marinara sauce or
pizza sauce, enhances the absorption of the nutrient. "The bottom line
is, if you want to do something positive for both your prostate and your
heart, don't smoke, eat less fat and eat your veggies," Stanford said.
"It certainly can't hurt."

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."