BBC News
December 10, 2004


The rate of childhood cancer has slowly increased over the last three
decades, research has found.

The International Agency for Research on Cancer, based in France,
examined data from 19 European countries.

It found cancer rates increased by around 1% a year for children, and
1.5% a year for adolescents between the 1970s and 1990s.

The research, which stresses cancer before age 20 is still rare, is
published in The Lancet.

The scientists say no single factor can be held responsible for the
rise, and the underlying causes are likely to be highly complex.

But they suggest lack of exposure to infections and an increase in
average birth weight may play a role, as may mixing of different

Some -- but not all -- of the rise might be explained by better
diagnosis of the disease, and better record keeping.

They analysed 113,000 cancers in children, and over 18,000 cancers in
adolescents during the 1970s, 1980s and 1990s.

They found the incidence rate by the 1990s was 140 per million for
children and 193 per million for adolescents.

The increases were recorded for virtually all tumour types in

In adolescents the major changes were seen for:

Carcinomas that develop in tissues covering or lining organs of the
body, such as the skin, the uterus, the lung, or the breast.

Lymphomas that develop in the lymphatic system, such as Hodgkins

Soft tissue sarcomas that begin in the muscle, fat, fibrous tissue,
blood vessels, or other supporting tissue of the body.

Germ-cell cancers that develop in the testicles or ovaries.

Tumours of the central nervous system.

Over the three decades studied survival rates increased substantially,
reaching a five-year survival rate of 75% for children in western
Europe, and 64% in eastern Europe.

Survival rates for adolescent patients were similar.

Lead researcher Dr Eva Steliarova-Foucher said: "Our results are clear
evidence of an increase of cancer incidence in childhood and
adolescence during the past decades, and of an acceleration of this

She added: "We can only speculate about the possible factors of this
increase, based on results of other research studies.

"But several studies have shown an association of the increased risk
of leukaemia with high birth-weight.

"Results concerning the age at bearing children are not consistent
among studies, but some have shown the risk increase with young and
advanced maternal age and advanced paternal age. Reducing crowded
housing postpones early infections, and was shown to be associated
with increased leukaemia risk. On the contrary, the attendance to day
care apparently reduces this risk. These factors are also indicators
of development of socio-economic status, which supports the finding of
increasing incidence of leukaemia with increasing socio-economic
status. Vaccinations can have double effect on the incidence. Studies
of vaccination against tuberculosis (BCG) have shown reduced risk of
childhood leukaemia, but also an excess of some lymphomas, occurring
later in life.

Devastating disease

Professor John Toy, medical director at the charity Cancer Research
UK, said: "Childhood cancer is uncommon but when it does occur it is
devastating for all those involved.

"While it is good news that survival is dramatically improving the
increase in incidence rates reported in this study are a cause for

"The study shines light on some possible causes for the increase, such
as population mixing and socioeconomic status.

"It is essential that researchers investigate these leads in order to
develop future prevention strategies.

"It is likely that a complex combination of environmental and genetic
factors are involved."

Also writing in The Lancet, Dr Catherine Cole, of the Princess
Margaret Hospital for Children in Perth, Australia, said most children
with cancer lived in developing countries.

And while 80% of children with cancer survived in the west, most in
developing countries die from lack of medical care.

"The challenge now is to ensure equity of access to cancer care for
all children.

"Centres of excellence should be developed in low-income countries to
train staff."

Copyright 2004 BBC News