Childhood cancer

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A girl trying out hats to wear after chemotherapy against a Wilms' tumor, which is a cancer type that typically occurs in children.[1]

Childhood cancer (also known as pediatric cancer) is cancer in a child. In the United States, an arbitrarily adopted standard of the ages used are 0–14 years inclusive, that is, up to 14 years 11.9 months of age.[2][3] However, the definition of childhood cancer sometimes includes young adults between 15–19 years old.[3] Pediatric oncology is the branch of medicine concerned with the diagnosis and treatment of cancer in children.

Epidemiology[edit]

Incidence and mortality[edit]

Worldwide, it is estimated that childhood cancer has an incidence of more than 175,000 per year, and a mortality rate of approximately 96,000 per year.[4]

In the United States, cancer is the second most common cause of death among children between the ages of 1 and 14 years, exceeded only by accidents.[5] More than 16 out of every 100,000 children and teens in the U.S. were diagnosed with cancer, and nearly 3 of every 100,000 died from the disease.[5] In the United States in 2012, it was estimated that there was an incidence of 12,000 new cases, and 1,300 deaths, from cancer among children 0 to 14 years of age.[6] Statistics from the 2014 American Cancer Society report:

Ages birth to 14[7]

Sex Incidence Mortality Observed Survival %
Boys 178.0 23.3 81.3
Girls 160.1 21.1 82.0

Ages 15 to 19[7]

Sex Incidence Mortality Observed Survival %
Boys 237.7 34.5 80.0
Girls 235.5 24.7 85.4

Note: Incidence and mortality rates are per 1,000,000 and age-adjusted to the 2000 US standard population. Observed survival percentage is based on data from 2003-2009.

In the UK, an average of 1,603 children per year were diagnosed with cancer in 2008-2010.[8] In 2007-2009, there was an average of 260 childhood deaths per year from cancer in the UK.[8]

In developed countries, childhood cancer has a mortality of approximately 20% of cases.[9] In low resource settings, on the other hand, mortality is approximately 80%, or even 90% in the world's poorest countries.[9]

Rates of childhood cancer have increased by 0.6% per year between 1975 to 2002 in the United States[10] and by 1.1% per year between 1978 and 1997 in Europe.[11]

Internationally, the greatest variation in childhood cancer incidence occurs when comparing high-income countries to low-income ones.[12] This may result from differences in being able to diagnose cancer, differences in risk among different ethnic or racial population subgroups, as well as differences in risk factors.[12] An example of differing risk factors is in cases of pediatric Burkitt lymphoma, a form of non-Hodgkin lymphoma that sickens 6 to 7 children out of every 100,000 annually in parts of sub-Saharan Africa, where it is associated with a history of infection by both Epstein-Barr virus and malaria.[12][13][14] In industrialized countries, Burkitt lymphoma is not associated with these infectious conditions.[12]

Risk factors[edit]

Familial and genetic factors are identified in 5-15% of childhood cancer cases. In <5-10% of cases, there are known environmental exposures and exogenous factors, such as prenatal exposure to tobacco, X-rays, or certain medications.[15] For the remaining 75-90% of cases, however, the individual causes remain unknown.[15] In most cases, as in carcinogenesis in general, the cancers are assumed to involve multiple risk factors and variables.[16]

Aspects that make the risk factors of childhood cancer different from those seen in adult cancers include:[17]

  • Different, and sometimes unique, exposures to environmental hazards. Children must often rely on adults to protect them from toxic environmental agents.
  • Immature physiological systems to clear or metabolize environmental substances
  • The growth and development of children in phases known as "developmental windows" result in certain "critical windows of vulnerability".

Also, a longer life expectancy in children avails for a longer time to manifest cancer processes with long latency periods, increasing the risk of developing some cancer types later in life.[17]

Types[edit]

The most common cancers in children are (childhood) leukemia (34%), brain tumors (23%), and lymphomas (12%).[11] In 2005, 4.1 of every 100,000 young people under 20 years of age in the U.S. were diagnosed with leukemia, and 0.8 per 100,000 died from it.[5] The number of new cases was highest among the 1–4 age group, but the number of deaths was highest among the 10–14 age group.[5]

In 2005, 2.9 of every 100,000 people 0–19 years of age were found to have cancer of the brain or central nervous system, and 0.7 per 100,000 died from it.[5] These cancers were found most often in children between 1 and 4 years of age, but the most deaths occurred among those aged 5–9.[5] The main subtypes of brain and central nervous system tumors in children are: astrocytoma, brain stem glioma, craniopharyngioma, desmoplastic infantile ganglioglioma, ependymoma, high-grade glioma, medulloblastoma and atypical teratoid rhabdoid tumor.[18]

Other, less common childhood cancer types are:[18]

Organizations[edit]

Organizations focused on childhood cancer through cancer research and/or support programs include: Childhood Cancer Canada, CLIC Sargent and the Children's Cancer and Leukaemia Group (in the United Kingdom), Child Cancer Foundation (in New Zealand), American Childhood Cancer Organization(in the United states),[19] Childhood Cancer Support (Australia) and the Hayim Association (in Israel).[20]

The International Childhood Cancer Day occurs annually on February 15.[9][21]

Learning problems[edit]

Children with cancer are at risk for developing various cognitive or learning problems.[22] These difficulties may be related to brain injury stemming from the cancer itself, such as a brain tumor or central nervous system metastasis or from side effects of cancer treatments such as chemotherapy and radiation therapy. Studies have shown that chemo and radiation therapies may damage brain white matter and disrupt brain activity.

References[edit]

  1. ^ EBSCO database verified by URAC; accessed from Mount Sinai Hospital, New York
  2. ^ Bahadur, G. (2000). "Age definitions, childhood and adolescent cancers in relation to reproductive issues". Human Reproduction 15: 227–221. doi:10.1093/humrep/15.1.227.  edit
  3. ^ a b Childhood Cancers: Basic Facts & Figures from Minnesota Department of Health. Retrieved Dec, 2012
  4. ^ About childhood cancer at Childhood Cancer 2012, by Children With Cancer UK
  5. ^ a b c d e f Cancer in Children from Centers for Disease Control and Prevention. Page last reviewed: July 30, 2009
  6. ^ Cancer Facts & Figures 2011 from American Cancer Society.
  7. ^ a b Ward, E; DeSantis, C; Robbins, A; Kohler, B; Jemal, A (Mar–Apr 2014). "Childhood and adolescent cancer statistics, 2014.". CA: a cancer journal for clinicians 64 (2): 83–103. PMID 24488779. 
  8. ^ a b Childhood cancer statistics at Cancer Research UK. Updated: 14 November 2012.
  9. ^ a b c International Childhood Cancer Day – 15 February 2013 at educationscotland.gov.uk. Retrieved Dec, 2012
  10. ^ Ward EM, Thun, MJ, Hannan, LM, Jemal, A (Sep 2006). "Interpreting cancer trends". Annals of the New York Academy of Sciences 1076: 29–53. Bibcode:2006NYASA1076...29W. doi:10.1196/annals.1371.048. PMID 17119192. 
  11. ^ a b Kaatsch P, Sikora, E, Pawelec, G (June 2010). "Epidemiology of childhood cancer". Cancer treatment reviews 36 (4): 277–85. doi:10.1016/j.ctrv.2010.02.003. PMID 20231056. 
  12. ^ a b c d Children and Cancer, in Children's Health and the Environment, a WHO Training Package for the Health Sector, World Health Organization. In turn citing: Scott CH. Childhood cancer epidemiology in low-income countries" Cancer 2007, 112;3:461-472
  13. ^ "Viral Cancers: Epstein-Barr virus". World Health Organization Initiative for Vaccine Research. Retrieved January 28, 2013. 
  14. ^ Moormann AM, Snider CJ, Chelimo K. (October 2011). "The company malaria keeps: how co-infection with Epstein-Barr virus leads to endemic Burkitt lymphoma". Current Opinion in Infectious Diseases 24 (24(5)): 435–41. doi:10.1097/QCO.0b013e328349ac4f. PMID 21885920. 
  15. ^ a b Children and Cancer, in Children's Health and the Environment, a WHO Training Package for the Health Sector, World Health Organization. In turn citing:
    • Birch JM. Genes & Cancer" Arch Dis Child 1999, 80:1-3.
    • Lichtenstein P et al" N Engl J Med 2000, 13;343(2) 78-85
  16. ^ Children and Cancer, in Children's Health and the Environment, a WHO Training Package for the Health Sector, World Health Organization. In turn citing: Anderson LM et al. Critical Windows of Exposure for Children’s Health: Cancer in Human Epidemiological Studies and Neoplasms in Experimental Animals Models. Environ Health Perspect, 2000, 108(suppl 3) 573-594.
  17. ^ a b Children and Cancer, in Children's Health and the Environment, a WHO Training Package for the Health Sector, World Health Organization.
  18. ^ a b Childhood Cancer overview from American Society of Clinical Oncology (ASCO). Retrieved January 2013
  19. ^ American Childhood Cancer Organization homepage
  20. ^ Hayim Association homepage
  21. ^ February 15th is International Childhood Cancer Awareness Day!!! at The Foundation for Children with Cancer (FCC). Retrieved Dec, 2012
  22. ^ Children Diagnosed With Cancer: Returning to School from American Cancer Society. Last Medical Review: 07/02/2012

 This article incorporates public domain material from websites or documents of the Centers for Disease Control and Prevention.