Some Asians Fare Better with Prostate Cancer
in US
< Aug.
15, 2007 > -- Your outlook for surviving
prostate cancer may depend on your racial and ethnic
background, a new study suggests.
Published in the medical journal, Cancer, the
study shows that compared to Caucasian men,
most Asian ethnic groups - except South Asians -
have better outcomes at the time of diagnosis. The
study is the first to report prostate cancer survival
data for Korean, South Asian, and Vietnamese men
living in the US.
"Nearly all Asians do far better
when they get prostate cancer," says study lead author
Dr. Anthony Robbins, of the California
Cancer Registry in Sacramento. "But Indian
men didn't do as well as other Asian men, and they
did worse than all other men, including blacks and
Caucasians," he adds.
The
reasons for these racial and ethnic differences
in prostate cancer survival are
not known, Dr. Robbins says, adding, "We just couldn't
explain it."
Not
only can the researchers not explain the finding,
they note an apparent paradox.
The Asian men were usually older and had more advanced
disease at the time of diagnosis, Dr. Robbins states. "Based
on their risk factors, you would think they were
going to do worse," he says.
In
the study, Dr. Robbins
and his co-researchers collected data on 116,916
men (108,076 Caucasians and 8,840 Asians from the
six largest represented Asian ethnicities - Chinese,
Filipino, Japanese, Korean, South Asian, and Vietnamese)
diagnosed with prostate cancer. The researchers compared
prognostic factors (which help predict the course
of disease) and survival rates among the men.
They found that for Asians, risk
profiles were worse compared with Caucasians. For
example, Asians were more likely to have more advanced
disease and use non-curative therapies. But, for
Asians - except for South Asians - survival rates
were still equal to or better than rates for Caucasians.
Japanese-American men were 34
percent less likely to die from prostate cancer compared
with Caucasians. But South Asian men - those from
India, Pakistan, Bangladesh, Sri Lanka, Nepal, and
Bhutan - were 40 percent more likely to die from
the disease, Dr. Robbins says.
Some of the factors that may influence
the findings include diet, exercise, and genetics,
Dr. Robbins speculates.
"Doctors that are seeing patients
for prostate cancer need to be aware that these differences
can be used as factors in planning the patient's
treatment and telling the patient what their survival
might be," Dr. Robbins says.
The risk among different Asian
ethnicities is poorly understood partly because most
studies have grouped all Asians into a single racial
category, ignoring the diverse ethnicities that make
up Asia.
Interestingly,
the most current data has shown that compared
to non-Hispanic Caucasian Americans, some Asian
ethnicities, such
as Japanese-Americans, have higher survival rates,
despite worse clinical disease, whereas others, such
as Filipino-Americans, have worse survival rates.
However, South Asians - e.g., Indians, Pakistanis,
Bangladesh, etc. - who represent the third largest
Asian subgroup in the US, have never been studied
for prostate cancer before.
Dr. Durado Brooks, director of
prostate and colorectal cancer at the American
Cancer Society (ACS), thinks this study confirms
the need to better understand how different racial
and ethnic groups respond to diseases.
"This study points out the potential
misleading conclusions we can come to when we use
these large groups to lump different subpopulations
into," he says.
"If you lump in the South Asian
subgroup with other Asians, as is traditionally done,
you totally miss the fact that these folks have a
strikingly higher chance of dying from prostate cancer," Dr.
Brooks says.
Dr. Brooks says the study finding
can provide a basis for research to try to understand
why these differences exist between populations.
The study should help physicians
more accurately apply prognostic factors to their
prostate cancer patients.
In conclusion, the study authors
say these results argue that traditional prognostic
factors for survival from prostate cancer such as
stage, grade, treatment, age, year of diagnosis,
and socioeconomic status, do not explain why most
Asian men have better survival compared to Caucasians.
But they do explain the poorer survival of South
Asian men compared to Caucasians.
Always consult your physician
for more information.
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or call our Physician Referral Service at 314-FOR-DOCS
Prostate cancer is the most
common cancer among men, excluding skin cancer. The American
Cancer Society (ACS) estimates
for 2007 include 218,890 new cases
of prostate cancer in the US.
Year 2007 estimates include 27,050 deaths
occurring from prostate cancer in the US alone, making it the
second leading cause of cancer death in men.
What is a risk factor? A
risk factor is anything that may
increase a person's chance of developing a disease. It may
be an activity, such as smoking,
diet, family history, or many other
things. Different diseases, including cancers, have different
risk factors.
Although these factors can increase a person's
risk, they do not necessarily cause the disease. Some people
with one or more risk factors never develop cancer, while others
develop cancer and have no known risk factors.
Knowing your risk factors to any disease can
help to guide you into the appropriate actions, including changing
behaviors and being clinically monitored for the disease.
What are risk factors
for prostate cancer? In general, all men are at
risk for prostate cancer. However,
there are specific risk factors that increase the likelihood
that certain men will
develop the disease, including
the following:
- Age is a risk factor for prostate
cancer, especially men age 50
and older. More than 70 percent
of all prostate cancers are diagnosed
in men over the age of 65.
- Prostate cancer is nearly 60
percent more common among African-American
men than it is among Caucasian-American
men. Japanese and Chinese men
native to their country have
the lowest rates of prostate
cancer.
- Data suggests
that the diet consumed in Western
industrialized
countries may be one of the most
important contributory factors
for developing prostate cancer.
- Dietary fiber intake may influence
circulating levels of testosterone
and estradiol, which, in turn,
may decrease the progression
of prostate cancer.
- Besides lower fat intake, another
major difference between Asian
and American diets is the consumption
of soy, averaging 35 g a day
per capita. Soy contains isoflavones
which, in several studies, have
been found to inhibit the growth
of prostate cancer.
- Carotenoids containing lycopenes
have been shown to inhibit the
growth of human prostate cancer
cells in tissue cultures (cells
grown in the laboratory). The
primary source of lycopenes is
processed tomatoes in tomato
juice and tomato paste.
- Having a father or brother
with prostate cancer more than
doubles or triples a man's risk
of developing this disease. The
risk is even higher for men with
several affected relatives, particularly
if the relatives were young at
the time of diagnosis.
Always consult your physician for more information.
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