Figure 153-1 Childhood Cancer: SEER Incidence Rates 2005–2009 by ICCC Group (includes myelodysplastic syndromes and Group III benign brain). Under 20 years of age, both sexes, all races. Source: SEER 18 areas (San Francisco, Connecticut, Detroit, Hawaii, Iowa, New Mexico, Seattle, Utah, Atlanta, San Jose-Monterey, Los Angeles, Alaska Native Registry, Rural Georgia, California excluding SF/SJM/LA, Kentucky, Louisiana, New Jersey, and Georgia, excluding ATL/RG). Rates are age-adjusted to the 2000 U.S. Std Population (19 age groups Census P25-1130).
International Classification of Childhood Cancer is based on ICD-O-3. (Steliarova-Foucher E, Stiller C, Lacour B, et al:
International Classification of Childhood Cancer, ed 3. Cancer 103(7):1457−1467, 2005.) *Rate for Group III (Brain/CNS) includes benign brain tumors.
commonly masquerades as a potential malignancy. In particular Epstein-Barr virus, cytomegalovirus, and mycobacterial infections can mimic leukemia or lymphoma by causingfever, lymphadenopathy, organomegaly, weight loss, andabnormal blood counts. Trauma may produce swelling thatcan mimic solid tumors. Idiopathic thrombocytic purpuraand iron deficiency can produce thrombocytopenia and anemia, respectively. Immune deficiencies or irregularities (autoimmune hemolytic anemia or neutropenia) can also producecytopenias. Juvenile idiopathic arthritis and other collagenvascular disease can cause musculoskeletal pain and anemia,mimicking leukemia. Benign tumors are relatively commonin children, including mature germ cell tumors/hamartomas,hemangiomas or other vascular tumors, mesoblastic nephromas, and bone cysts.
A CBC with differential and review of the peripheral blood smear is the best screening test for many pediatric malignancies. Leukopenia (with or without neutropenia), anemia, or thrombocytopenia may be present in leukemia or any cancer that invades the bone marrow (e.g., neuroblastoma, rhabdomyosarcoma, and Ewing sarcoma). Leukemia may also produce leukocytosis, usually with blasts present on the peripheral blood smear. An isolated cytopenia (neutropenia, anemia, or thrombocytopenia) widens the differential diagnosis but still could be the only abnormal laboratory finding. Of note, a
Table 153-1 Known Risk Factors for Selected Childhood Cancers CANCER TYPE RISK FACTOR COMMENTS Acute lymphoid leukemia Ionizing radiation Prenatal diagnostic x-ray exposure increases risk. Therapeutic irradiation for cancer treatment also increases risk.
Genetic conditions Down syndrome is associated with an estimated 10to 20-fold increased risk. Neurofibromatosis 1, Bloom syndrome, and ataxia-telangiectasia, among others, are associated with an elevated risk.
Acute myeloid leukemias Chemotherapeutic agents Alkylating agents and epipodophyllotoxins increase risk.
Genetic factors Down syndrome and neurofibromatosis 1 are strongly associated. Familial monosomy 7 and several other genetic syndromes are also associated with increased risk. Patients treated with radiation therapy for other cancers.
Brain cancers Therapeutic ionizing radiation to the head
Genetic factors Neurofibromatosis 1 is strongly associated with optic gliomas and, to a lesser extent, with other central nervous system tumors. Tuberous sclerosis and several other genetic syndromes are associated with increased risk.
Hodgkin disease Family history Monozygotic twins and siblings are at increased risk.