Porth's Essentials of Pathophysiology, 4e

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Cell and Tissue Function

U N I T 1

Unfortunately, there are no early warning signs or screening tests for cancer in children. 70,71 Prolonged fever, persistent lymphadenopathy, unexplained weight loss, growing masses (especially in association with weight loss), and abnormalities of central nervous system func- tion should be viewed as warning signs of cancer in chil- dren. Because these signs and symptoms of cancer are often similar to those of common childhood diseases, they are frequently attributed to other causes. Diagnosis of childhood cancers involves many of the same methods that are used in adults. Histologic exami- nation is usually an essential part of the diagnostic pro- cedure. Accurate disease staging is especially beneficial in childhood cancers, in which the potential benefits of treatment must be carefully weighed against potential long-term treatment effects. The treatment of childhood cancers is complex and continuously evolving. It usually involves appropri- ate multidisciplinary and multimodal therapy, as well as the evaluation for recurrent disease and late effects of the disease and therapies used in its treatment. The treatment program should include specialized teams of health care providers. 72 Several modalities are frequently used in the treat- ment of childhood cancer, with chemotherapy being the most widely used, followed in order of use by surgery, radiotherapy, and biologic agent therapy. Chemotherapy is more widely used in treatment of children with cancer than in adults because children better tolerate the acute adverse effects, and in general, pediatric tumors are more responsive to chemotherapy than adult cancers.

Radiation therapy is generally used sparingly in children because they are more vulnerable to the late adverse effects. As with care of adults, adequate pain manage- ment is critical.

Survivors of Childhood Cancers With improvement in treatment methods, the number of children who survive childhood cancer is continuing to increase. 73–76 As a result of cancer treatment, almost 80% of children and adolescents with a diagnosis of cancer become long-term survivors. 72 Unfortunately, radiation and chemotherapy may produce late sequelae, such as impaired growth, neurologic dysfunction, hor- monal dysfunction, cardiomyopathy, pulmonary fibro- sis, and risk for second malignancies (Table 7-5). There is a special risk of second cancers in children with the retinoblastoma gene. Thus, one of the growing chal- lenges is providing appropriate health care to survivors of childhood and adolescent cancers. Children reaching adulthood after cancer therapy may have reduced physical stature because of the ther- apy they received, particularly radiation, which retards the growth of normal tissues along with cancer tissue. The younger the age and the higher the radiation dose, the greater the deviation from normal growth. There is concern about the effect that CNS radiation has on cognition and hormones that are controlled by the hypothalamic-pituitary axis. Children younger than 6 years of age at the time of radiation and those receiving

Long-term Effects of Childhood Cancer Treatment

 TABLE 7-5

System

CancerTreatment

Risk

Cardiac

Radiation, chemotherapy (anthracyclines)

Cardiomyopathy, conduction abnormalities, valve damage, pericarditis, left ventricular dysfunction Reduction in lung volume with exercise intolerance, restrictive lung disease Kidney hypertrophy or atrophy, renal insufficiency or failure, hydronephrosis Pituitary, thyroid, and adrenal dysfunction; growth failure; ovarian and testicular failure; delayed secondary sex characteristics; obesity; infertility

Pulmonary

Radiation, chemotherapy (carmustine, lomustine, bleomycin) Radiation, chemotherapy (platinums, ifbsfamide and cyclophosphamide, cyclosporine A), nephrectomy Radiation, chemotherapy (alkylating agents)

Renal/urological

Endocrine

Central nervous system Radiation, intrathecal (injected into subarachnoid or subdural space) chemotherapy

Learning disabilities

Musculoskeletal and bone

Radiation, chemotherapy (alkylating agents, topoisomerase II inhibitors), amputation Radiation, chemotherapy (anthracyclines, alkylating agents, vinca alkyloids, antimetabolites), and corticosteroid medications Radiation, chemotherapy (alkylating agents, epipodophylotoxins)

Disordored limb growth, disorders of ambulation and limb use

Hematologic and lymphatic systems

Leukemia Lymphoma

Second malignancy

Solid tumors, leukemia, lymphoma, brain tumors

Information from: Schmidt D, Anderson L, Bingen K, et al. Late effects in adult survivors of childhood cancer: Considerations for the general practitioner. WMJ. 2010;109(2):98–107; and HendersonTO, Friedman DL, Meadows AT. Childhood cancer survivors:Transition to adult-focused risk-based care. Pediatrics. 2010;126:127–136.