Childhood cancer


Childhood cancer is cancer in a child. About 80% of childhood cancer cases in high-income countries can be treated with modern treatments and good medical care. Although treatment and care are available, only 10% of children with cancer reside in high-income countries. Globally, children with cancer account for approximately 1% of all cancer diagnosis annually. The majority of children with cancer are in low- and middle-income countries, where it is responsible for 94% of deaths among those under 15 years old, because new cancer treatments are not easily available in these countries. For this reason, in low and mid-income countries, childhood cancer is often ignored in control planning, contributing to the burden of missed opportunities for its diagnoses and management.
Even with improved care, childhood cancer survivors face ongoing risks of recurrence and secondary cancers. Rates of childhood cancer deaths have steadily declined since 2003, but rates of pediatric cancer are on the rise. The biggest increase has been seen in thyroid carcinomas, lymphoma, and hepatic tumors. Pediatric cancer patients face additional challenges in education, income, and social support compared to the general population and their siblings.
In the United States, an arbitrarily adopted standard of the ages used is 0–14 years inclusive, up to age 14 years 11.9 months. However, the definition of childhood cancer sometimes includes adolescents between 15 and 19 years old. Pediatric oncology is the branch of medicine concerned with the diagnosis and treatment of cancer in children.

Signs and symptoms

Common childhood malignancies can be categorized by the International Classification of Childhood Cancer, which is a standardized method created by the World Health Organization.

Risk factors

Risk factors are any genetic or environmental exposure that increases the chances of developing a pathological condition. Some examples are age, family history, environmental factors, genetics, and economic status among others. Several chromosomal disorders and constitutional syndromes are also associated with childhood cancer.

Demographic risk factors

  • Childhood cancer varies by age, sex, ethnicity, and race. Its incidence peaks in infancy with about 240 cases/million/year.
  • This rate decreases to 128 cases per million from five–nine years of age, and it rises again to 220 cases/million.
  • Slight male dominance for most childhood cancers.

    Environmental factors

  • High-dose ionizing radiation and certain forms of prior chemotherapy are established risk factors for childhood cancer, each increasing cancer risk severalfold.

    Genetic factors

Identified Cancer Predisposition Syndromes
  • Li–Fraumeni syndrome
  • Hereditary breast or ovarian cancer
  • Colorectal cancer/polyposis syndromes
  • Familial retinoblastoma
  • Familial and genetic factors are identified in 5–15% of childhood cancer cases. In <5–10% of cases, there are known environmental exposures and exogenous factors, such as prenatal exposure to tobacco, X-rays, or certain medications. For the remaining 75–90% of cases, however, the individual causes remain unknown. In most cases, as in carcinogenesis in general, the cancers are assumed to involve multiple risk factors and variables.
Aspects that make the risk factors of childhood cancer different from those seen in adult cancers include:
  • Different, and sometimes unique, exposures to environmental hazards. Children must often rely on adults to protect them from toxic environmental agents.
  • Immature physiological systems to clear or metabolize environmental substances
  • The growth and development of children in phases known as "developmental windows" result in certain "critical windows of vulnerability".
Also, a longer life expectancy in children allows for a longer time to manifest cancer processes with long latency periods, increasing the risk of developing some cancer types later in life.
Advanced parental age has been associated with an increased risk of childhood cancer in the offspring. There are preventable causes of childhood malignancy, such as delivery overuse and misuse of ionizing radiation through computed tomography scans when the test is not indicated or when adult protocols are used.

Diagnosis

Types

The most common childhood cancers are leukemia, central nervous system tumors, and lymphomas. The main subtypes of brain and central nervous system tumors in children are: astrocytoma, brain stem glioma, craniopharyngioma, desmoplastic infantile ganglioglioma, ependymoma, high-grade glioma, medulloblastoma and atypical teratoid rhabdoid tumor. In 2020–2022, 1.9 per 100,000 children died from cancer.
In 2022, an estimated 4.2 per 100,000 individuals in the United States younger than 20 years were diagnosed with leukemia, and 0.6 per 100,000 died from the disease. In the same year, 2.3 per 100,000 individuals in this age group were diagnosed with cancers of the brain or central nervous system, and 0.6 per 100,000 died from these tumors. The incidence of both leukemia and brain or central nervous system cancers in children and adolescents has declined since 2016 and 2018, respectively.
Other, less common childhood cancer types are:
  • Neuroblastoma
  • Wilms tumor
  • Non-Hodgkin lymphoma
  • Childhood rhabdomyosarcoma
  • Retinoblastoma
  • Osteosarcoma
  • Ewing sarcoma
  • Germ cell tumors
  • Pleuropulmonary blastoma
  • Hepatoblastoma and hepatocellular carcinoma
  • Juvenile myelomonocytic leukemia

    Diagnostic Methods

In all cases of suspected cancer, evaluation should begin with a thorough history and physical examination. Techniques used for definitive diagnoses vary by the suspected cancer itself. The first step in evaluation of solid tumors is often imaging of the affected organ or tissue, though a biopsy is typically required for a definitive diagnosis.
For the most common childhood cancer, acute lymphoblastic leukemia, evaluation typically begins with a complete blood count and peripheral blood smear. Lymph node biopsy and flow cytometry may also be utilized, and a bone marrow biopsy is required for definitive diagnosis. Imaging is usually not needed for non-solid tumors such as leukemia, unless metastasis is suspected or there are other concerning examination findings.
Other common diagnostic tests include the following:
Overall, treating childhood cancer requires a multidisciplinary team of doctors, nurses, social workers, therapists, and other community members. Here is a brief list of doctors that can treat childhood cancer:
  • Pediatric oncologist: These doctors specialize in treating childhood cancers.
  • Pediatric hematology-oncologist: These doctors specialize in treating blood diseases in children.
  • Pediatric surgeon: These doctors specialize in performing surgery on children.
  • Adolescent and young adult oncology : AYA is a branch of medicine that deals with the prevention, diagnosis, and treatment of cancer in adolescents and young adults, often defined as those aged 13–30. Studies have continuously shown that while pediatric cancer survival rates have gone up, the survival rate for adolescents and young adults has remained stagnant. Additionally, AYA helps patients with college concerns, fertility, and a sense of aloneness. Studies have often shown that treating young adults with the same protocols used in pediatrics is more effective than adult-oriented treatments.
Other specialties that can assist the treatment process include radiology, neurosurgery, orthopedic surgery, psychiatry, and endocrinology.

Treatment

Childhood cancer treatment is individualized and varies based on the severity and type of cancer. In general, treatment can include surgical resection, chemotherapy, radiation therapy, or immunotherapy.
Recent medical advances have improved our understanding of the genetic basis of childhood cancers. Treatment options are expanding, and precision medicine for childhood cancers is a rapidly growing area of research.
The side effects of chemotherapy can result in immediate and long-term treatment-related comorbidities. For children undergoing treatment for high-risk cancer, more than 80% experience life-threatening or fatal toxicity as a result of their treatment.

Psychosocial care

Psychosocial care of children with cancer is also important during the cancer journey, but the implementation of evidence-based interventions need to be further spread across pediatric cancer centers. In general, psychosocial care can include therapy with a psychologist or psychiatrist, referral to a social worker, or referral to a pastoral counselor. Family-centered psychosocial care is one approach that can be used to not only support the patient's psychosocial well-being but also support the parents and any caregivers of the patient.

Play therapy

One type of psychosocial care for children with cancer is play therapy, which means that the child is using an essential part of childhood to increase mental and physical well-being while reducing the negative emotions that come from being in the hospital. Children need to engage in play, even if they are in a hospital. Some types of play therapy use distraction tactics for intervening on anxiety, while also allowing children to communicate their feelings by reflecting on abilities and emotions that they are using as they adapt to the new environment of the hospital.
There are multiple types of play therapy, including medical play, pretend play, or direct play. Medical play reduces anxiety and stress by using medical tools or equipment to explain fears of treatments, procedures, and hospital settings. Other types of play therapy include drawing therapy, painting therapy, puzzle therapy, and storytelling. Drawing, painting, storytelling, and puzzle play therapy are relaxing techniques that do not take too much energy from the patient, so they can avoid fatigue while also engaging in psychosocial and mental development, and creativity. Further, these are accessible types of therapy for children as they are easy to engage in, affordable, and liked by children.
Drawing, painting, puzzle therapy, and storytelling as play therapy techniques all help to reduce anxiety and fear in a hospital setting, which also helps to increase cooperative behavior in children with cancer. Play therapy is effective not only for just the children but also for improving relationships between hospital staff and children. Improving this relationship can lead to children being more open about their fears and anxieties and help them gain a sense of independence.
In children with leukemia, it has been found that play therapy decreases adverse psychosocial outcomes, like pain and fatigue.