Chapter 13: Cancer in Children and Adolescents

Although childhood cancer represents a rare diagnosis, it remains the leading cause of disease-related mortality in this population, though survival rates have improved dramatically to exceed eighty percent due to advances in multimodal therapeutic approaches, chemotherapy regimens, clinical trial participation, and enhanced supportive care measures. The incidence of childhood cancer follows a bimodal age distribution, with peaks in children under five years old and again during adolescence, affecting approximately eighteen per one hundred thousand children annually, with slightly higher prevalence in boys and white populations. Unlike adult carcinomas that arise from epithelial tissues and develop through prolonged environmental exposure, most pediatric cancers originate from mesodermal germ layers, producing hematologic malignancies, sarcomas, lymphomas, and embryonal tumors including neuroblastoma and retinoblastoma, with leukemias and central nervous system tumors comprising the largest disease categories. The etiology of childhood malignancy involves genetic predisposition syndromes such as Down syndrome, Fanconi anemia, Bloom syndrome, Beckwith-Wiedemann syndrome, neurofibromatosis, and Li-Fraumeni syndrome characterized by TP53 mutations, alongside chromosomal translocations and germline mutations in tumor-suppressor genes like RB1 and WT1 that increase susceptibility to specific cancer types. Environmental contributors include prenatal exposures to diethylstilbestrol and ionizing radiation, childhood exposures through radiation therapy and chemotherapy, and viral infections including Epstein-Barr virus and HIV-related malignancies, though causative relationships remain incompletely understood. Prognosis varies significantly between age groups and tumor types, with adolescents experiencing lower cure rates partly attributable to reduced clinical trial enrollment and distinct tumor biology, while long-term survivors face substantial morbidity including secondary malignancies, reproductive dysfunction, neurocognitive impairment, bone atrophy, and psychosocial sequelae due to treatment effects during critical developmental periods.