Belarus children with thyroid cancer

["Franta, Jaroslav" <frantaj@aecl.ca>]

Noteworthy quotes in this article:

"In the current study, the research team looked at 483 children with thyroid
cancer who were living in Belarus at the time of the accident." and
"After an average of nearly 4 years of follow-up, none of the children had
died from cancer"


http://www.reutershealth.com/eline/open/2000031521.html
Radiation hits very young the hardest 
NEW YORK, Mar 15 (Reuters Health) -- Exposure to radiation, such as that
released by the Chernobyl nuclear plant accident, takes a heavier toll on
very young children, according to new study findings. 
Among children living in Belarus, thyroid cancer was more common and more
severe in children who were younger than 2 years old at the time of the 1986
accident than in those who were older, researchers report. In addition, the
rate of childhood thyroid cancer was considerably higher in girls than in
boys. 
Radiation released by the nuclear accident at Chernobyl led to an increased
rate of thyroid cancer in children living in regions surrounding the plant.
Previous research has shown that younger children were at greatest risk of
developing cancer, but whether or not a child's age affected the severity of
the disease has not been studied closely, according to a team of researchers
led by Dr. Jamshid Farahati, of the University of Wurzburg in Germany. 
In the current study, the research team looked at 483 children with thyroid
cancer who were living in Belarus at the time of the accident. All of the
children were younger than 8 years old when exposed to radiation from the
plant. 
As has been reported before, the greatest number of cancer cases occurred in
children who were younger than 2 years old at the time of the accident,
Farahati and colleagues report in the March 15th issue of Cancer, a journal
of the American Cancer Society. The investigators also found that the rate
of cancer was 60% higher in girls than in boys. 
But the researchers note that cancer tended to be more severe in the
youngest children. In youngsters under age 2, tumors had grown outside the
thyroid gland 62% of the time, compared with just 40% in children aged 6 to
8 years old. In addition, the youngest children were more likely to have
cancer spread to the lymph nodes and other parts of the body, according to
the report. But despite the differences in disease severity, the lag time
between radiation exposure and cancer diagnosis was similar in all children.

The authors explain that thyroid cells in infants and toddlers divide
rapidly as the glands mature. Since cancer depends on mutations that occur
during cell division, each time a cell divides is an opportunity for cancer
to take hold. In contrast, older children have more mature thyroid glands,
so the pace of cell division is slower, which may explain in part why the
risk of thyroid cancer is lower in older children. And since thyroid glands
in younger children tend to be smaller than in older kids, the same amount
of radiation may have more of an effect, leading to more severe cancer,
according to the report. 
After an average of nearly 4 years of follow-up, none of the children had
died from cancer, Farahati and colleagues report. However, they state that
these children should continue to be followed to see what effect, if any,
age at the time of radiation exposure has on long-term survival. 
SOURCE: Cancer 2000;68:1470-1476. 

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