Childhood cancer studies

Many studies have been carried out on the effects of environmental chemical exposure and carcinogenesis in children, beginning in utero and through their teens. The following are representative of these studies where chemical mixtures were shown to be causative. Other examples are examined in the next chapter on cancer clusters. 

Epidemiological evidence shows that prenatal exposure to cigarette smoke, chlorinated hydrocarbons, and other organic solvents increases the incidence of cancer in offspring, as carcinogens are transferred from the mother to the fetus via the placenta.  

Prenatally exposed mice exposed to cigarette smoke approximately equivalent to less than one pack of cigarettes per day demonstrated a greater than two-fold increase in tumor incidence when challenged at 5 weeks of age with EL4 lymphoma cells.  

One study demonstrated that parental occupational exposures to chlorinated hydrocarbons are associated with increased risks for leukemia, lymphoma, and urinary tract cancers in offspring. Another study showed associations between maternal exposures to solvents and increased incidences of leukemia. These solvents include 1,1,1-trichloroethane, toluene, and other mononuclear aromatic hydrocarbons, mineral spirits, and alkanes. Childhood brain cancers, the second leading cause of childhood cancer, have been associated with parental occupational exposures to toxic chemicals. Industries for which such associations have been found include 10  

The authors of this review study point out that although frequently there are positive associations between parental occupation and childhood brain cancers, these associations are inconsistent. These inconsistencies are attributed to the use of chemicals from different sources of supply with varying additives. 10 Put another way the different supplies contain different chemical mixtures that may be the responsible agents. 

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Gunier. R. B., Harnly, M. E., Reynolds. P, Hertz, A., and Von Behren, I. (2001). Pesticide use in California Pesticide prioritization, use densities, and population distributions for a childhood cancer. study. Environ. Health Perspeci. 109, 1071-1078. 

Leiss, J. K., and D. A. Savitz. (1995). Home pesticide use and childhood-cancer A case control study. American Journal of Public Health 85(2) 249-252. Zahm, Sheila H., and Mary H. Ward. (1998). Pesticides and childhood cancer. Environmental Health Perspectives 106(Suppl. 3) 893-908. 

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer with a erne rate of approximately 80%. However, despite the generally favorable outeome of ALL treatment, some children relapse or experience severe treatment side effeets. Reeent research eiforts have focused on understanding the patient genetie eharaeteris-ties that underlie treatment response. To date, several studies have demonstrated that... 

Leiss, J.K. and Savitz, D.A. (1995) Home pesticide use and childhood-cancer-a case-conttol study. American Journal of Public Health, 85, 249-52. 

An avenue for both occupational and enviromnental exposure assessment which has only rarely been used in case-control studies is direct exposure measurements of the study subjects. For pesticides with long biological half-lives, and whose concentrations are unlikely to be affected by the disease, biological measures of exposure can be made. For example, Caldwell etal. (1981) and Scheele etal. (1992, 1996) measured pesticide levels in bone marrow and serum in adult and childhood cancer cases and controls. 

The relation between neonatal vitamin K administration and childhood cancer has been investigated in three case-control studies. 

In a retrospective study 685 children who developed cancer before their 15th birthday were compared with 3442 controls matched for date and hospital of birth (29). There was no association between the administration of vitamin K and the development of all childhood cancers (unadjusted odds ratio 0.89 95% Cl = 0.69,1.15)... 

Passmore SJ, Draper G, BrownbUl P, Kroll M. Case-control studies of relation between childhood cancer and neonatal vitamin K administration. BMJ 1998 316(7126) 178-84. 

Golding J, Paterson M, Kinlen LJ. Factors associated with childhood cancer in a national cohort study. Br J Cancer 1990 62(2) 304-8. 

Human exposures to RF radiation arise from military use, industrial use, broadcasting, and cellular phone use. These exposures have been linked to increased numbers of spontaneous abortion, neurological effects, altered red and white blood cell counts, increased somatic mutation rates in lymphocytes, cardiovascular effects, increased cancer risk, and increased childhood cancers/28 311 Other studies.however, have refuted these findings) 27,32 As stated in the introduction, only a relatively few studies addressed the combined effects of toxic chemical and RF exposure. A thorough search of the literature shows that such studies have not been refuted. The following are illustrative examples of these mixture studies. 

Meyers A, Clayden AD, Cartwright RA, Cartwright SC. Childhood cancer and overhead power lines A case-control study. BrJCancer 1990 62 1008-14. 

Carcinogenic effects of environmental mixtures on children are not limited to in utero exposures. In a study conducted on children who resided in two of the most polluted cities in the Silesia province of Poland, it was found that simultaneous exposure to PAHs and lead (emissions from coalburning stoves) led to the induction of cytogenic effects in peripheral lymphocytes. I11 A study in Great Britain found that childhood cancers are strongly elevated by both prenatal and early postnatal exposures to oil-based combustion gases, particularly from engine exhausts. 121... 

Oeffinger KC, Mertens AC, Sklar CA et al (2006) Childhood Cancer Survivor Study. Chronic health conditions in adult survivors of childhood cancer. N Engl J Med 355 1572-1582... 

The subcommittee is aware of a suspected cancer cluster in Fallon, Nevada, and that exposure to JP-8, originating from a naval base located in that town, is under investigation as a possible cause of the cluster (exposures to other chemicals are being investigated as well). Since 1997, sixteen persons currently or previously living in Fallon have been diagnosed with acute lymphocytic leukemia (ALL), a type of childhood cancer. One case of ALL would be expected approximately every 5 yr in Churchill County, where Fallon is located, based on the size of the population (Nevada State Flealth Division 2002). No scientific studies were found that examined a potential relationship between ALL and JP-8 exposure therefore, the subcommittee could not reach any conclusion concerning exposure to JP-8 and this suspected cancer cluster. 

One of the most thoroughly researched epidemiology studies has been conducted at Eallon, Colorado. There was a belief that the number of childhood cancers (acute lymphocytic leukemia) in that tovm was above expected values. GDC sampled soil, air, water, and many other mediums looking for a cause. They... 

Much of the epidemiological evidence pertaining to parental occupational exposure as a risk factor for childhood cancer and leukemia is inconsistent or even contradictory and this could be explained, at least for some of the data, by the different study designs, different sources of data, poor definition of the level, and period of exposure [3]. 

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