Recognizing Cancer in Children 01/22/2010

Resident: J. Hencler
Date: 01/22/2010

Article title: Recognizing Cancer in Children
Author(s): William H. Schultz
Journal: Journal of the American Academy of Physician Assistants
Volume #2; Number 5; Pg 338-352
Year: 1989

Major topic: Cancer in children

Type of Article: Review of current information

Main Purpose:
Increase the practitioner’s awareness of childhood cancer to aid in better diagnosis

Overview of method of research: Review of current information

Background and discussion:
An estimated 6500 cancers are diagnosed each yr in children, most common of which are leukemia, lymphomas, or brain tumors.
Etiology: Common cancers in children involve tissues that are not in direct contact with the environment. Genetic predisposition is more important in causing cancer in children than are environmental agents. (Table 1) Disorders with preexisting chromosomal aberrations, such as Down syndrome and Bloom syndrome, are associated with a high risk of leukemia. Also, a few childhood cancers are inherited such as retinoblastoma.
Diagnosis: The clinical features of childhood cancer are not obvious because signs and symptoms are usually nonspecific. Diagnosis is often delayed because major complaints are usually attributed to minor causes. Lymph node enlargement, fever, weakness, weight loss, cough, and shortness of breath are common symptoms associated with infectious diseases but are also cardinal features of malignancies. (Table 2) Even though most pediatric tumors have already metastasized before diagnosis, early detection of an asymptomatic tumor enhances the child’s prognosis.
Management: Emotional support for family should be provided. Children treated at pediatric cancer centers with state of the art protocols have a higher disease free survival rate than do children treated elsewhere. Supportive care must be provided to manage the acute complications of aggressive cancer therapy. These may include erythrocyte/platelet transfusion and broad spectrum antibiotics. Infections are the leading cause of death in children with cancer. Patients undergoing cancer therapy should not be vaccinated with live virus preparations.

Common Childhood Malignancies:

1. Acute Leukemia: Hematologic malignancies including leukemia and lymphomas, comprise the majority of cancers seen in children. Leukemia arises in the bone marrow and is a cancer of the leukocytes and progresses to bone marrow dysfunction and infiltration of tissues. A triad of anemia, neutropenia, and thrombocytopenia is a common consequence of dysfunctional bone marrow. Hematologic manifestations of leukemia are due to bone marrow replacement with malignant cells. Significant bone pain results when the marrow cavity becomes packed with leukemic cells. (Table 3) Erythrocyte mass and oxygen carrying capacity of the blood is decreased resulting in fatigue, irritability, pallor, tachycardia, and dyspnea. Acute lymphocytic leukemia is the most prevalent childhood leukemia. Bone marrow aspiration is the definitive test for leukemia. Before starting therapy a spinal tap is done to determine any CNS involvement. Most protocols call for 3 years of therapy. Bone marrow transplant may be required during therapy.

2. Brain Tumors: CNS tumors are the second most common childhood cancer. The clinical features of most childhood brain tumors are due to increased intracranial pressure caused by spinal fluid obstruction. (Table 4) Older children may have history of morning headache, vomiting, dizziness, or change in behavior. CT scan and MRI are the most specific tests to determine intracranial neoplasm. Surgical resection and irradiation therapy are the treatment for childhood brain tumors.

3. Lymphomas: Lymphomas are a diverse group of cancers of the immune system. Included in this group of lymphoid cancers are Hodgkin’s disease (HD) and non-Hodgkin’s lymphoma (NHL). Progressive cervical lymph node enlargement without associated symptoms is the most common early clinical manifestation of HD in children. Painless hard lymph nodes frequently represent metastatic cancer. In NHL, the gastrointestinal tract and mediastinum are primary disease sites more often than peripheral lymph nodes. Diagnosis of lymphoma is based upon histologic examination of involved tissues. Treatment of localized, early stage HD may consist of radiation alone but more advanced disease may require either involved-field or extended-field radiation combined with multiagent chemotherapy. NHL must be regarded as microscopically disseminated at diagnosis and always requires chemotherapy. The diagnosis for children with abdominal tumors is more favorable when complete excision is possible.

4. Neuroblastoma (Nb): Arises from neural crest tissues of the sympathetic nervous system and demonstrates a diversity of primary sites from the base of the skull to deep in the pelvis. Most occur in the retroperitoneal area. Nb is the most frequently discovered malignant tumor in infants. Children diagnoses after the age of 2 do much worse than those who are younger at diagnosis. Nb frequently causes nonspecific symptoms that sometimes mimic common pediatric illnesses. Vanillylmandelic acid and homovanillic acid are metabolites whose levels are elevated in Nb and can be easily measured in the urine for diagnostic purposes. Total surgical excision of localized tumor can achieve a 2 year survival rate greater than 80%. Unfortunately most Nb is widespread at diagnosis. Post operative chemotherapy and irradiation may shrink an unresectable tumor.

5. Wilms’ Tumor (WT): Is a primary malignancy of mixed histologic features occurring in the kidney. It is the most common abdominal neoplasm in children. WT is often discovered when the child’s abdomen enlarges or an abdominal mass is found. Symptoms include malaise, constipation, anorexia, or fever. It is usually palpated unilaterally but a small percentage of cases involve both kidneys. Treatment protocol may include radiotherapy, adjunctive chemotherapy, or surgical nephrectomy depending on staging.

6. Osteosarcoma (Os): Is a relatively rare bone cancer that affects adolescents. The tumor usually arises in the long bones in the metaphyseal region, where growth is more active. The femur, tibia and humerus are frequent sites of primary tumor involvement, with most originating around the knee. A Common symptom of Os is pain and swelling at the primary site. Histologic examination of tissue obtained with an open biopsy confirms the diagnosis. With the ability to identify intramedullary tumor extension, more conservative surgical approaches can be tried, such as cross-bone amputations and “limb sparing” procedures. Adjunctive chemotherapy for Os is a common treatment protocol.

Fortunately, cancer in children is rare. Early diagnosis and appropriate referral is so important and may greatly improve prognosis.

Assessment of article:
Good article. May be a little outdated at 21 years old but still relevant to the pediatric dentist who should have some knowledge of the cancer types that commonly affect our patient population.