[ RadSafe ] NEWS: Testicular cancer on the rise in much of the world

[John Jacobus]

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Testicular cancer on the rise in much of the world
6/29/2005
By: Reuters Health


NEW YORK (Reuters Health), Jun 29 - Though testicular
cancer remains relatively uncommon, rates of the
disease have risen in many countries since the 1970s,
a new study shows.

Testicular cancer is known to be most common among
white men, and worldwide, rates of the disease are
still highest in the U.S., Canada, Australia and
Europe -- particularly in Nordic countries such as
Denmark and Norway. 

But researchers at National Cancer Institute in
Bethesda, Maryland, have found that rates of the
disease rose between 1973 and 1997 in many parts of
the world -- including traditionally low-incidence
countries.

It's "implausible," the researchers report in the
International Journal of Cancer, that better diagnosis
of the disease explains the rise, since there is no
widespread screening for the cancer and most men are
still diagnosed only after symptoms arise. 

Instead, Dr. Mark P. Purdue and his colleagues
speculate, changes over time in certain risk factors
for testicular cancer may be at work. What those
factors are, however, is unclear, according to the
researchers.

Testicular cancer, which usually arises in young men,
remains a relatively rare disease, even in countries
considered high-incidence. In the U.S., the disease
accounts for about 1% of all cancers diagnosed in men.

Researchers have identified certain risk factors for
the disease -- such as white race, family history of
testicular cancer, or being born with an undescended
testicle or certain other congenital abnormalities. 

But the role of factors related to lifestyle and
environment has been hard to pin down.

According to Purdue's team, some studies have
suggested that men whose mothers gave birth to them at
an older age have an elevated risk of testicular
cancer, possibly due to elevated levels of maternal
estrogen during pregnancy. 

Other theorized risk factors include low birthweight,
younger age at puberty and certain viral infections in
childhood. None of these, however, have been
conclusively tied to testicular cancer. 

More research into how suspected risk factors have
changed over time in different populations "may yield
important insight into the causes of the widespread
increase in testis cancer risk," Purdue and his
colleagues write. 

Their study is based on 25 years' worth of data from
international cancer registries. Overall, rates of
testicular cancer between 1973 and 1997 were highest
in Denmark and lowest in Zimbabwe. 

But over time, rates of testicular cancer rose in
every population studied -- by 60%, on average --
though the increases were strongest mainly in the
regions that have traditionally had the highest
incidence. In the U.S., the incidence among white men
climbed 47%, compared with 23% among black men. 

And in Nordic countries, cancer rates rose anywhere
from 59% to 86%.

One standout was Puerto Rico, a low-incidence region
that nonetheless had the biggest jump in the rate of
testicular cancer, at 220%. This, however, is a
reflection of the "extremely low" incidence seen in
Puerto Rico in the 1970s, the researchers note. 

On the brighter side, there were some signs that in
the 1990s, the rise in testicular cancer was leveling
off in the U.S. and certain other regions. Further
research of more recent data, according to Purdue's
team, should help show whether rates are indeed
stabilizing. 

Last Updated: 2005-06-29 13:12:11 -0400 (Reuters
Health)

SOURCE: International Journal of Cancer, July 10,
2005. 

Copyright © 2005 Reuters Limited.

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"Every now and then a man's mind is stretched by a new idea and never shrinks back to its original proportion." -- Oliver Wendell Holmes, Jr.

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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