Childhood cancer corresponds to a group of several diseases that have in common the uncontrolled proliferation of abnormal cells and that can occur anywhere in the body. Unlike adult cancer, childhood cancer usually affects the cells of the blood system and supporting tissues (while in adults it usually affects the cells of the lining epithelium of different organs).
In most cases, tumors in children and adolescents are made up of undifferentiated cells, which allows for a better response to treatments. The chances of cure, survival and quality of life of the patient are greater the earlier the cancer is diagnosed.
Treatment should be performed in a specialized pediatric center, by a multidisciplinary team, individually for each specific histological type and according to the clinical extent of the disease.
With current therapeutic regimens, approximately 80% of children can be cured.
Types of childhood cancer
The following are the most common tumors in childhood and adolescence:
- Leukemia – is the most common type of childhood cancer. It affects the bone marrow and other organs outside the bone marrow, such as the central nervous system, testicles and eyes;
- Brain and central nervous system tumor – second most common type in children, accounting for 26% of childhood cancers. There are many types of brain tumors, with different treatment and prognosis; and
- Lymphomas that affect the lymphatic system – often affect the lymph nodes and lymph tissues such as the tonsils or thymus. The bone marrow and other organs can also be affected.
Other types of cancer that also affect children and adolescents:
- Neuroblastoma – a type of tumor of cells of the peripheral nervous system, often located in the abdomen. It accounts for about 6% of childhood cancers. This type of cancer occurs in infants and toddlers and is rare in children over 10 years of age;
- Wilms tumor – starts in one kidney, rarely affecting both. Most often diagnosed in children aged 3 to 4 years. It represents 5% of childhood cancers;
- Retinoblastoma – tumor that affects the retina, that is, the back of the eye. It represents about 2% of childhood cancers. It usually occurs in children in the age group of 2 years of age and is rarely diagnosed after 6 years of age. When shining a light into a child’s eye, it is normal for the pupil to appear red, due to blood from the vessels at the back of the eye. In the eye with retinoblastoma, the pupil appears white or pink. This white glow in the eye is often seen in photos taken with a flash;
- Germ tumor – occurs in cells that originate the ovaries and testicles;
- Bone tumor: the two main types are osteosarcoma and Ewing’s sarcoma. Osteosarcoma develops in areas where bone is growing, such as the long bones of the legs or arms. Ewing’s tumor can affect bones, muscles or cartilage; and
- Rhabdomyosarcoma – starts in cells that normally develop in skeletal muscles, which help body movement. It can occur in the head and neck, groin, abdomen, pelvis or limbs (arms or legs). It represents about 3% of childhood cancers.
Symptoms and signs of childhood cancer
In most cases symptoms are related to common childhood diseases, which highlights the importance of consulting a pediatrician to monitor the children’s health.
The main warning signs for childhood cancer are the following:
- Bruising or bleeding for no apparent reason;
- Bone pain;
- Lumps or bumps without trauma;
- Unexplained weight loss;
- Persistent cough or shortness of breath;
- Night sweats;
- Eye changes (white pupil, new-onset squint, visual loss, bruising or swelling around the eyes);
- Abdominal distension;
- Headaches associated with vomiting (especially in the morning or worsening over the days);
- Pain in limbs;
- Fatigue, lethargy or changes in behavior; and
- Dizziness, loss of balance or coordination.
Diagnosis of childhood cancer
Childhood cancers are rare, and there are no recommended screening tests to detect the disease in children who are not at increased risk. Children who are more likely to develop a specific type of cancer, because of certain genetic changes inherited from one parent, may need careful, regular medical examinations.
When there is suspicion, an imaging study guides the initial procedure to be performed in cases of solid tumors. In some cases, a surgical approach for complete tumor resection is possible. When this is not viable, a biopsy will be performed to provide the histopathological diagnosis and enable the beginning of chemotherapy treatment; tumor resection will take place at a second stage.
The goal is always to avoid surgeries that cause too much damage to the patient.
Cancer treatment comprises three therapeutic modalities, namely: surgery, chemotherapy and radiotherapy. Treatment will be indicated to each patient based on their individual condition, according to the tumor diagnosed and taking into account the extent of the disease.
Children with cancer have special needs that may be best served at centers specializing in childhood cancer. Treatment involves a multidisciplinary team that must include pediatricians (oncologists, surgeons, cardiologist, nephrologist, endocrinologist, ophthalmologist, gastroenterologist), radio-oncologists, pediatric nurses, psychologists, social workers, nutritionists, physiotherapists, dermatologist, orthopedist, neurologist, neurosurgeon, dentist and occupational therapist.
Childhood and adolescence are critical periods of development. In them, in addition to the formation of life habits, exposure to environmental factors can affect the structure or function of organs or tissues, compromising adult health.
In this sense, it is essential to provide guidance on known risk factors for cancer related to long-term exposure, such as lack of regular physical exercise, inadequate nutrition, exposure to unprotected ultraviolet radiation (UVA and UVB rays from the sun), tobacco and alcohol use, non-vaccination against infectious agents (such as hepatitis B and HPV) and sexual intercourse without the use of condoms.