The types of cancers in children are very different from adults. Cancers in adults usually have a known cause. However, in children very few cancers are caused by environmental or lifestyle factors. The most common types of childhood cancers include leukemias, brain cancers, lymphomas, and solid tumours like Neuroblastoma and Wilm’s tumour.
Leukemias which are the most common childhood cancers are cancers of the bone marrow and blood. More than a third of all childhood cancer are caused by them. They are of 2 types: acute and chronic. However, most childhood leukemias are acute.
Acute leukemia is of further 2 types: acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML). Of the two, ALL is around three times more common than AML. The symptoms of leukemias are most often due to problems in the bone marrow.
As leukemia cells build in the marrow, they take the place of normal blood cells. As a consequence of this, child does not have normal red blood cells, white blood cells and platelets. Due to lack of red blood cells, child has low haemoglobin which results in fatigue, dizziness, shortness of breath and paleness of skin. The paucity of normal white blood cells leads to infections. A low platelet count results in bleeding manifestations. Leukemia cells can also invade other parts of the body and cause symptoms. A very common symptom of leukemia is bony pains which occurs due to build-up of leukemia cells near the surface of bone or inside the joint. Acute leukemia can also present with lymphadenopathy, hepatomegaly and splenomegaly. If diagnosed early and managed by a well-trained paediatric Haemato-oncologist, ALL has an excellent prognosis and cure rate.
The second most common type of childhood cancers are brain and spinal cord cancers which account for around one-fourth of childhood cancers. There are numerous forms of brain and spinal cord tumours, each with its unique presentation and therapeutic options.. Around 50 percent of the brain tumours seen in children are gliomas which include astrocytomas, oligodendrogliomas, ependymomas, brainstem gliomas and optic gliomas. Of these, the most commonly seen gliomas are astrocytomas.
Other types of brain tumours seen in children are embryonal tumours, pineal tumours, craniopharyngiomas, mixed glial and neuronal tumours, choroid plexus tumours, schwannomas, meningiomas and germ cell tumours. Most of tumours arise from cerebellum or brainstem in children. The most common symptoms of brain cancers are headache, nausea, vomiting, blurred vision or diplopia, dizziness and seizures. Spinal cord tumours are rare in children.
The cell of origin for lymphomas is lymphocyte. Lymphomas arise from the lymph nodes or other lymphatic tissues, like tonsils or thymus. They can also have an impact on the bone marrow and other organs. The symptoms of lymphomas depend on their site causing enlargement of lymph nodes along with some universal symptoms like weight loss, fever and night sweats. The 2 main types of lymphomas are Hodgkin lymphoma and non-Hodgkin lymphoma. Both these types occur in children as well as adults.
Hodgkin lymphoma accounts for around 3 percent of childhood cancers. It is more commonly seen in adolescent population and in late adulthood. It is extremely rare in children under the age of five. The presentation and treatment is similar in children and adults.
Non-Hodgkin lymphoma accounts for 5 percent of childhood cancers. It is relatively uncommon in children under the age of three. It is, nevertheless, more common in younger children than Hodgkin’s lymphoma. Non-Hodgkin lymphoma in children is distinct from non-Hodgkin lymphoma in adults. Although non-Hodgkin lymphoma seen in children is more aggressive than adults, it responds better to therapy.
Approximately 6 percent of childhood cancers are neuroblastomas. Neuroblastoma is mainly seen in infants and young children and is uncommon in children older than 10 years of age. Neuroblastoma can often be asymptomatic. The most common symptom is painless abdominal mass. Other symptoms are fever, bone pain, diarrhea, skin lesions, etc.
Wilm’s tumour, also known as nephroblastoma, is responsible for 5 percent of all cancers in Childhood . It is mostly unilateral but rarely can be bilateral. It is mainly seen in children less than 5 years of age and presents as abdominal mass. Other symptoms like fever, pain and haematuria can also be seen.. Wilm’s tumour makes up roughly 5 percent of all childhood cancers.
Retinoblastoma is a type of eye tumour. It accounts for about 2 percent of all childhood malignancies. It is most common in children under the age of two.The most common presenting feature is leucocoria (white pupil).
Around 3 percent of childhood cancers are bone tumours. They are seen more commonly in older children. The two common types seen in children are osteosarcoma and Ewing’s sarcoma. The two most common symptoms of bone tumours are pain and swelling.