| Chapter 2: | Background |
|
|
For example, specific chemicals such as benzene, asbestos, vinyl chloride, arsenic, and aflatoxin show definite evidence of causing cancer in humans, while others (i.e., chloroform and formaldehyde) are considered possible carcinogens based on evidence collected through animal experiments (American Cancer Society, 2007). Radiation exposure in the form of high-frequency ionizing radiation (IR) and ultraviolet (UV) radiation has also been proven to cause cancer, based on evidence from studies of atomic bomb survivors, patients receiving radiotherapy, and certain occupational groups, such as uranium miners (American Cancer Society, 2007). Overall, though, it appears that the etiology of most childhood cancers in unknown, although it is theorized that the etiology is most likely attributable to a complex interaction between environmental factors and genetic susceptibility that varies in specifics among the different forms of cancer (American Cancer Society, 2007; Li & Wendt, 1998). Clearly, continued research is necessary to formally document how environmental and genetic factors interact in the etiology of childhood cancer.
Diagnosis, Prognosis, and Course of Childhood Cancer
Cancers in children are often difficult to recognize. Consequently, parents are encouraged to have their children receive regular medical checkups and be alert for unusual symptoms, including the following: an unusual mass or swelling; unexplained paleness and loss of energy; a sudden tendency to bruise; a persistent, localized pain or limping; prolonged, unexplained fever or illness; frequent headaches, often with vomiting; sudden eye or vision changes; and excessive, rapid weight loss (American Cancer Society, 2007; Li & Wendt, 1998). A diagnosis of cancer typically involves a careful systematic assessment using diagnostic radiology (i.e., X-rays), surgery, and/or biochemistry, in order to determine the stage of the disease and the presence/absence of favorable or unfavorable prognostic factors (Li & Wendt, 1998).