Child Cancer Rates Have Increased 34% Since 1975

Despite a fall in overall cancer rates over the last decade or so, child cancer rates have continued to increase steadily and are now up 34% since 1975 recent data from SEER shows. Overall age adjusted cancer rates have been falling since the late 1990s and are now 10% below their peak. Child cancer rates on the other hand have increase steadily by around 1% per year and show no sign of peaking.

Fortunately, most childhood cancers are easily treatable with a 5-year survival rate of 83.9% for cancers diagnosed in those under 20 compared to 66.7% for the general population.

What is concerning however is that both radiation and chemotherapy have long lasting effects on the body and as a result, survivors of childhood cancer have an increased risk of developing heart disease or cancer in later life.

The most common forms of cancer in children are: bone cancers, soft tissue cancers, brain and other central nervous system cancers, cancers of the eye, testicular cancer, leukaemias, and lymphomas. Combined, these account for around three-quarters of all childhood cancers.

The graph below shows the percentage change in cancer incidence from 1975 to 2008 for the most common child cancer sites.

Change In Childhood Cancer Rates 1975-2008

Overall, childhhod cancers rates have increased from 12.9 to 17.3 per 100,000 children per year (an increase of 34%). Cancer types that have shown the greatest increases include melanoma, which has increased by 84%, testicular cancer (75% increase), brain cancer (42% increase), and leukaemia (38% increase).

The increase in melanoma rates is due partly to improved screening leading to earlier detection of the disease and partly because of increases in levels of UV radiation due to depletion of the ozone layer. While the effect is most pronounced at high and low latitudes, even areas in mid latitudes have experienced modest increases in UV radiation. A 2010 study, published in the Journal Of Geophysical Research, found that UV levels at a latitude of 32.5 degrees, which runs through Texas, were 9% higher in 2009 compared to 1979. Prolonged exposure to high levels of UV radiation is the strongest risk factor for melanoma.

The huge increase in the rate of testicular cancer is believed to be the result of greater exposure to endocrine disruptors which are chemicals that interfere with hormones in the human body. Common endocrine disruptors include DDT (a commonly used insecticide during the 20th century), PCBs (used as industrial coolants and lubricants), and BPA (a compound found in most plastic bottles and the lining of food and beverage cans).

There has been much debate about whether magnetic fields generated by high voltage power lines and electric appliances in the home can cause cancer. In particular, several studies have found that living near high voltage power lines may increase the risk of childhood leukaemias and possibly brain cancer. While we will not discuss the issue in detail in this article the current scientific consensus is that there is limited evidence that chronic exposure to magnetic fields above 0.4 micro-Tesla (a level typically exceeded by those living within 100m of high voltage power lines) is associated with around a two-fold increase in the risk of children developing leukaemia however their is insufficient evidence of a link between magnetic fields and other forms of childhood cancer.

Mobile phones are another area of concern with the International Agency for Research on Cancer (IARC) classifying mobile phones as possibly carcinogenic to humans this year. Although mobile phones may potentially raise the risk of developing brain cancer, it is unlikely to be the cause of the increasing rates of brain cancer observed in children because children don’t normally begin to use mobile phones until they are 11 or 12. Given that the lag time between exposure to a carcinogen and the development of cancer is normally in excess of 15-20 years, any increase in brain cancer rates as a result of mobile phone use would be restricted to middle aged and elderly individuals. Furthermore, teens and young adults are more likely to use their mobile phones to SMS and surf the internet rather than make phone calls.