Common childhood cancers

Worldwide leukaemia is the most common childhood cancer, accounting for about one third of all cases. The next most common childhood cancers  are brain tumours and lymphomas, followed by embryonal tumours and sarcomas. Primary healthcare workers sometimes do not know much about  childhood cancer because it is a rare disease and most primary healthcare workers do not see many (if any) cases in their practice. 

Embryonal tumours are a type of cancer that develops from cells left over from foetal development, specifically in the central nervous system  (CNS). They are typically found in babies and young children, and the most common type is medulloblastoma. These tumours are characterized by  their rapid growth and tendency to spread within the CNS. 

Sarcoma is a rare type of cancer that develops in the body's connective tissues, which include bone, muscle, fat, nerves, blood vessels, and cartilage.  It is categorized into two main types: bone sarcoma (originating in bone) and soft tissue sarcoma (originating in soft tissues like muscle, fat, etc.). 

When cancer affects the blood, it is called Leukaemia. Blood cells are produced in the red bone marrow, a spongy material inside the flat bones of the  body, but the lymph glands, spleen and thymus gland (behind the breastbone) also play a role.

There are three different types of blood cells: 

1. White blood cells – lymphocytes (T-cells and B-cells) and the precursor cells of neutrophils, which are important in fighting infections.
2. Red blood cells, which carry oxygen around the body, via the haemoglobin. 
3. Platelets help blood to clot and control bleeding.  

Leukaemia occurs when one of the types of blood cells changes into a cancerous cell that is no longer under the body’s control. These abnormal cells  divide and multiply in number but do not form a lump or tumour. Instead, the abnormal cells take over the bone marrow and spread via the bloodstream  into the lymph glands, spleen and the rest of the body. Leukaemia cells are called blasts.

There are 3 main types of Leukaemia: 

1. Acute Lymphoblastic Leukaemia (ALL) which develops from the lymphocytes. 
   1. https://cansa.org.za/files/2021/01/Fact-Sheet-on-Childhood-Acute-Lymphoblastic-Leukaemia-NCR-2017-web-January-2021.pdf 
   2. https://pmc.ncbi.nlm.nih.gov/articles/PMC4250840/ 
   3. https://www.stjude.org/care-treatment/treatment/childhood-cancer/leukemia-lymphoma/acute-lymphoblastic-leukemia-all.html 
   4. https://www.leukaemia.org.au/blood-cancer/types-of-blood-cancer/childhood-blood-cancers/childhood-all
2. Acute Myeloid Leukaemia (AML) which develops from the precursor cells of neutrophils, and rarely from the red cells and platelet making  cells (megakaryocytes). 
   1. https://www.hopkinsmedicine.org/kimmel-cancer-center/cancers-we-treat/blood-bone-marrow-cancers/leukemia-program/acute myelogenous-leukemia 
   2. https://www.cancer.gov/types/leukemia/patient/child-aml-treatment-pdq
   3. https://cansa.org.za/files/2021/01/Fact-Sheet-on-Childhood-Acute-Myeloid-Leukaemia-NCR-2017-web-January-2021.pdf 
3. Juvenile Myelomonocytic Leukaemia (JMML) which is characterized by the overproduction of immature white blood cells (myelocytes and  monocytes) which crowd out healthy blood cells in the bone marrow and other organs. 
   1. https://www.cancerresearchuk.org/about-cancer/childrens-cancer/juvenile-myelomonocytic-leukaemia-jmml 
   2.  https://pmc.ncbi.nlm.nih.gov/articles/PMC8010610/ 
   3. https://www.leukaemia.org.au/blood-cancer/types-of-blood-cancer/childhood-blood-cancers/juvenile-myelomonocytic leukaemia/ 
   4. https://www.akronchildrens.org/kidshealth/en/parents/jmml.html 
   5. https://cansa.org.za/files/2021/03/Fact-Sheet-on-Juvenile-Myelomonocytic-Leukaemia-NCR-2017-web-March-2021.pdf 
       

Most common symptoms  

• The child may develop a persistent infection because the production of normal white blood cells decreases and causes the body’s immune  system cannot function properly.  
• Abnormal bruising, petechiae (small red dots under the skin) and even bleeding (especially nose and gums) as the platelet count falls.  
• The child develops pallor (anaemia) as the red blood cell count decreases. The child may feel unwell and weak.  
• The child complains of aches and pains in the limbs (the marrow space is stretched) and abdomen (liver, spleen and nodes become full of  cells). 
• Usually, symptoms only manifest after about 12 weeks when the bone marrow is completely taken over by the Leukaemia cells.

Brain tumours are the second most common cancer in childhood. There are many different forms of brain tumours. A few are benign (non-cancerous), and others are malignant (cancerous). The majority of brain tumours in children are malignant. Brain tumours do not usually spread throughout the  body but can spread within the brain and spinal cord. Tumours in the brain stem can never be removed. Benign or malignant brain tumours each cause  similar physiological problems.

Most common symptoms 

The different types of brain tumour do not behave in the same way, so the child will not necessarily have all the symptoms described below. The skull  is like a closed box. Any tumour growing inside will increase the pressure on the brain. Because of this increased pressure, the child may have the  following symptoms. 

• Headache - often more severe in the morning. 
• Early morning projectile vomiting (may only be once or twice a day). 
• Drowsiness. 
• Hydrocephalus, the result of spinal fluid damming up inside the brain (normally the spinal fluid escapes through very narrow channels at the  base of the brain) because a tumour blocks the flow of spinal fluid. 
• Irritability. 
• Loss of appetite. 
• Lack of interest in school and other activities. 
• Some brain tumours disturb hormone production in the body, which can slow down growth in the child, delay the onset of puberty and produce  large quantities of urine. 
   

If the tumour presses on certain brain cells or nerves the child may have some or all the following symptoms.

• Early morning headaches due to raised intracranial pressure. 
• Muscle weakness, unsteadiness when walking or running, clumsiness and/or shaking when using one arm or leg. 
• Double vision or squint. 
• Difficulty swallowing, slurred speech. 
• Convulsions.

If a young baby has a brain tumour, the skull is less like a closed “box” because the sutures haven’t connected yet. This can cause the whole head to  increase in size and bulge. The soft spot (anterior fontanelle) on the top of the head may bulge due to the tumour blocking the normal flow of  cerebrospinal fluid.
 

READ MORE 

• CANSA Fact Sheet on Gliomas. https://cansa.org.za/files/2021/02/Fact-Sheet-on-Childhood-Gliomas-NCR-2017-web-February-2021.pdf • Brain Tumour Foundation of Canada. https://www.braintumour.ca/ 
• John Hopkins Medicine - Brain tumours in Children. https://www.hopkinsmedicine.org/health/conditions-and-diseases/brain tumor/pediatric-brain-tumors 
• Children's Cancer Institute Sydney. https://www.ccia.org.au/about-childhood-cancer/brain-cancer 
   

Tumours that start in the lymph glands are called lymphomas. The body's lymphatic system is made up of a collection of lymph nodes, each the size  of a pea. These nodes are connected by lymphatic vessels (similar to veins) which circulate fluid and cells. The main function of the lymphatic system  is to control infection and provide a collection and transportation system for white blood cells that help fight infections in the body. There are two main  types of lymphomas in children: 

1. Hodgkin Lymphoma 
   1. Relatively slow growing. 
   2. Predictable spread. 
   3. Good prognosis and a higher cure rate depending on the stage. 
2. Non-Hodgkin’s Lymphoma 
   1. Grows rapidly. 
   2. Unpredictable spread. 
   3. Prognosis depends on the type. 

Most common symptoms 

• Both types of lymphoma present in the same way: the enlargement of a group of glands somewhere in the body, perhaps in the neck, chest  or abdomen.
• Large glands on one or both sides of the neck, which do not go away when treated with antibiotics. The glands are not tender or sore to touch. A large nodal mass in the chest can cause cough, breathlessness (especially when lying down), difficulty in swallowing solid food and swelling  of the neck, face and eye puffiness. There may be fluid on the lungs as well. 
• Abdomen – swelling of the tummy with lumps or fluid, abdominal pain, constipation and bilious vomiting (if the intestines are blocked). • Other symptoms include fever, tiredness, anaemia, loss of appetite and weight loss, night sweats and pruritus (itching) in Hodgkin’s  Lymphoma. 
   

READ MORE 

• What is Childhood Cancer Lymphoma?https://jamanetwork.com/journals/jamapediatrics/fullarticle/2824010#google_vignette 
• The Children & Young People's Cancer Association (Leicester). https://www.cclg.org.uk/about-cancer/cancer-teenagers-and-young adults/types-cancer-teenagers-and-young-adults/lymphoma 
  
   

Wilms tumour (a tumour that affects the kidney) is one of the types of embryonal tumours in childhood cancer. Note that this is hardly seen in Japan!  It is quite different from the cancers that affect the kidneys of adults. Most patients are under 5 years old and usually only one kidney is affected. It is  very rare that both kidneys are affected. Many children are diagnosed too late with advanced stage disease, which requires more intensive treatment,  yet stage 4 Nephroblastoma still has a reasonable prognosis. 

Most common symptoms  

Symptoms are usually non-specific, and parents usually only become suspicious when they notice the child's tummy becoming swollen or feeling  particularly firm or hard. Sometimes the child may have pain in the abdomen, fever or blood in the urine. 

READ MORE 

• American Cancer Association: What are Wilms tumours. https://www.cancer.org/cancer/types/wilms-tumor/about/what-is-wilms tumor.html 
• CANSA Fact Sheet. https://cansa.org.za/files/2021/06/Fact-Sheet-on-Wilms-Tumour-and-Other-Childhood-Kidney-Tumours-NCR-2017- web-June-2021.pdf
• Wilms Tumour Foundation. https://www.wilmsfoundation.org/diagnosisandtreatment 
• Boston's Children's Hospital. https://www.childrenshospital.org/conditions/wilms-tumor 

ABSTRACT 

• Wilms’ tumour in African children: Can an institutional approach improve outcome? https://pmc.ncbi.nlm.nih.gov/articles/PMC4955494/ 
   

This tumour grows from nerve cells that run in a chain along the bones of the child’s spine in the neck, chest and abdomen or the adrenal gland. The  most common site for this tumour is the abdomen. The second most common site is the chest. In about 25% of patients, the tumour starts in the  adrenal gland, which sits on top of the kidney. In about 10% of patients, the tumour starts in the neck in the paraspinal nerve tissue. Most patients are  younger than 5 years old and it is very rare in children older than 10 years of age.

Most common symptoms  

• Initially the symptoms are vague and can easily be mistaken for a viral infection. Long before neuroblastoma is diagnosed, the child may fail  to gain weight, have recurrent and unexplained fever and complain of intermittent abdominal pain and fatigue. 
• Sometimes the tumour is discovered by accident when a chest x-ray is taken to rule out pneumonia due to infection of the upper respiratory  tract. 
• A hard, painless lump may be felt in the abdomen or neck. The glands in the neck and groin may be enlarged and there may be masses in the  skin as well as the scalp. 
• Children may appear to be chronically ill, irritable, in pain and anaemic. 
• Occasionally, an abnormally fast heartbeat, high blood pressure, sweating and fever can occur. 
• If the abdomen is swollen, the child may complain of a vague abdominal pain, fatigue, flu-like symptoms and loss of appetite. 
• Pain in the limb or back and refusal to walk and limping, may be present if the tumour has spread to the bone or bone marrow. 
• Leg weakness or even paralysis may occur if the tumour has spread into the spinal canal and is pressing on the spinal cord. 
• A tumour in the chest or neck might press on a nerve causing a drooping eyelid, a dilated pupil and an inability to sweat on one side of the  face (Horner's syndrome). 
• In some cases, the tumour produces a hormone that causes chronic and watery diarrhoea. 
• Jerky muscle spasms and uncontrolled eye movements (“dancing eyes”). 
• Periorbital ecchymosis with proptosis (raccoon eyes) when the tumour cells invade the orbit causing obstruction in the vessels. 
•  Abdominal distension (usually indicates metastases in the liver). 

READ MORE 

• CANSA Fact sheet on Childhood Neuroblastoma. https://cansa.org.za/files/2021/02/Fact-Sheet-on-Childhood-Neuroblastoma-NCR-2017- web-February-2021.pdf 
• Nemours KidsHealth USA. https://kidshealth.org/en/parents/neuroblastoma.html 
• Clevelend Clinic. https://my.clevelandclinic.org/health/diseases/14390-neuroblastoma 
• MSD - Global Medical Knowledge (Merck & Co). https://www.msdmanuals.com/home/children-s-health-issues/childhood cancers/neuroblastoma#Diagnosis_v822719 

The light sensitive lining of the eye is known as the retina. A malignant tumour of the retina is called Retinoblastoma. In about two-thirds of cases, only  one eye (unilateral disease) is affected. Sometimes a tumour develops in the other eye some months after the first diagnosis. This is most common in  children less than one year old and is not usually inherited. One-third of children develop tumours in both eyes (bilateral disease), but they usually  have a genetic or hereditary form of retinoblastoma, which tends to develop during the first year of life. Therefore, a healthcare worker should ensure  that siblings are referred to an ophthalmologist for screening if there is bilateral retinoblastoma. 

Most common symptoms 

• “White reflex” or cat's eyes, where the yellowish-white tumour can be seen through the pupil. Often this can be seen in photographs taken  even before there is a diagnosis. 
• Inward or outward turning of the eye – squint.  
• Sudden loss of vision 
• Abnormal appearance of the eye 
• Proptosis (bulging eyeball)
• Unequal pupils (usually occurs together with the pupil appearing white when the tumour fills the entire eye 
• If the tumour has spread, there can be swellings in the scalp and enlargement of lymph nodes in the neck or in front of the ears.

READ MORE 

• MSD - Global Medical Knowledge (Merck & Co). https://www.msdmanuals.com/home/children-s-health-issues/childhood cancers/retinoblastoma 
• American Academy of Ophthalmology. https://www.aao.org/eye-health/diseases/what-is-retinoblastoma
• Cancer Research UK. https://www.cancerresearchuk.org/about-cancer/childrens-cancer/eye-cancer-retinoblastoma/about. 
• NHS England. https://www.nhs.uk/conditions/retinoblastoma/symptoms/ 
• Texas Children's Hospital. https://www.texaschildrens.org/content/conditions/retinoblastoma

Rhabdomyosarcoma is the most common of a group of tumours known as ‘Soft Tissue Sarcomas’. There are several slightly different types of these  tumours, which grow in muscles or sinews or in the fibrous tissues around the muscles. They are most common in children between birth and five  years of age, but they can occur at any age.  

Most common symptoms

Rhabdomyosarcoma can occur anywhere in the body where there is muscle. Symptoms vary according to the primary site of the tumour. The first sign  is usually swelling, but the child will be well at the time of diagnosis unless the tumour has spread to distant sites in the body. 

• If the tumour is in the eye socket, the most common sign is protrusion of the eye. 
• Tumours in the sinus cause a blocked nose and bloody nasal discharge. 
• Tumours that affect the nerves in the face and head cause paralysis of the facial muscles or abnormal movements of the eyes or eyelids.  Other symptoms can include headache, vomiting and high blood pressure. 
• Tumours in the bladder and prostate cause blood in the urine or difficulty in passing urine. Other symptoms include a mass in the pelvis or  constipation.
• Girls who have a tumour of the cervix or vagina will have extrusion of tissue (grape-like) from within the vagina or a bloody or mucinous  discharge. 
• Boys with a tumour in the testicle will have enlarged lymph nodes or a lump in the scrotum. 
• If the tumour is in a limb (arm or leg), the child will have pain at the site and an obvious lump. The lymph nodes under the arm or in the groin  may be swollen. 
• A tumour in the chest usually only causes symptoms when the tumour has grown large enough to cause compression on the airway or other  structures, which may cause coughing, chest pain and rapid breathing.

READ MORE 

• MSD - Global Medical Knowledge (Merck & Co). https://www.msdmanuals.com/home/children-s-health-issues/childhood cancers/rhabdomyosarcoma
• NHS England. https://www.nhsinform.scot/illnesses-and-conditions/cancer/cancer-types-in-children/rhabdomyosarcoma/ 
• American Cancer Society - Signs and Symptoms of Rhabdomyosarcoma.  
  https://www.cancer.org/cancer/types/rhabdomyosarcoma/detection-diagnosis-staging/signs-symptoms.html 
   

This is the most common type of bone cancer in children. Most patients are between 10 and 20 years old when they are undergoing the growth spurt  at puberty. It is more common in boys and mostly affects the long bones at the growth plates which occur at each end of the long bones. The most  common site is the leg, and it involves the femur (upper leg) more frequently. The next most common sites are the tibia (lower leg) and the humerus  (upper arm). Osteosarcoma can also be a complication of radiation therapy for another type of cancer, such as rhabdomyosarcoma. Ewing sarcoma  and retinoblastoma can occur between 7 and 15 years after radiation treatment. 

Most common symptoms

• Pain in the affected body part. 
• Limited movement of the limb. 
• A lump and swollen lymph nodes in the affected area. 
• Tenderness and increased heat in the area.
• Trauma does not cause osteosarcoma but often just brings it to medical attention; for example, an unexplained fracture caused by the  tumour is often perceived as the trauma causing the cancer!

READ MORE 

• CANSA: Fact Sheet on Childhood Osteosarcoma. https://cansa.org.za/files/2021/02/Fact-Sheet-on-Childhood-Osteosarcoma-NCR-2017- web-February-2021.pdf 
• Johns Hopkins Medicine – Osteosarcoma. https://www.hopkinsmedicine.org/health/conditions-and-diseases/sarcoma/osteosarcoma 
• Children's Hospital of Philadelphia - Osteosarcoma (Bone cancer in children). https://www.chop.edu/conditions-diseases/osteosarcoma in-children

This is the second most common type of bone cancer in children and young adults. The Ewing sarcoma family of tumours is part of a group of tumours  that share certain characteristics. There are two separate types which both share the same chromosomal translocation between chromosome 11 and  chromosome 22. 

• Ewing sarcoma, which most often involves the bones but can involve soft tissue surrounding the bones. 
• Primitive neuroectodermal tumour (PNET) which involves bone and soft tissue or nerve tissue. 

These tumours can occur in any part of the body, but the most common sites are the pelvis, arms, legs and the ribs.

Most common symptoms

• Pain at the site of the primary tumour. 
• Swelling at the site of the tumour. 
• Some patients might have fever or experience weight loss.  
• If the tumour is near the spinal cord, the symptoms include weakness in the legs and loss of bladder control. 
• Sometimes Ewing sarcoma can be confused with an infection of the bone (osteomyelitis), and this can cause a delay in diagnosis.

READ MORE 

• CANSA Fact Sheet on Ewing’s Sarcoma. https://cansa.org.za/files/2021/03/Fact-Sheet-on-Ewings-Sarcoma-NCR-2017-web-March 2021.pdf 
• NHS England - Ewing Sarcoma: Children. https://www.nhsinform.scot/illnesses-and-conditions/cancer/cancer-types-in-children/ewing sarcoma-children/ 
• Boston Children's Hospital: What is Ewing sarcoma? https://www.childrenshospital.org/conditions/ewing-sarcoma 
• St Jude Care & Treatment: Ewing Sarcoma Treatment. https://www.stjude.org/care-treatment/treatment/childhood-cancer/solid tumors/ewing-sarcoma.html

Cancer of the liver is quite rare in children, accounting for only 1-2% of childhood cancers. It is a foetal tumour found in children younger than three  years and is the most common type of liver cancer. It is highly curable. Some other childhood cancers can spread to the liver, but these are very  different from primary liver cancer. Another type of liver cancer, hepatocellular carcinoma, is more common in children aged 12 to 15 years (and adults)  and may be associated with Hepatitis B infection. (Hepatitis B vaccinations have resulted in hepatocellular carcinoma becoming largely preventable).

Most common symptoms 

The first sign is usually a lump (mass) in the right upper side of the abdomen. Other symptoms may be present for many months before a diagnosis is  made and include: 

• a vague feeling of fullness in the abdomen, 
• pain in the abdomen, 
• vomiting, 
• diarrhoea, 
• fever, 
• abnormal weight loss, 
• jaundice (yellow appearance of the skin and sclera (whites) of the eyes). This is a very late sign and goes together with pruritus (itching).
   

READ MORE 

• CANSA - Fact Sheet on Childhood Hepatoblastoma. https://cansa.org.za/files/2021/02/Fact-Sheet-on-Childhood-Hepatoblastoma-NCR 2017-web-February-2021.pdf 
• St Jude Children's Research Hospital - Liver Cancer in Children and Teens. https://together.stjude.org/en-us/conditions/cancers/liver cancer.html 
• National Cancer Institute (USA): Childhood Liver Cancer. https://www.cancer.gov/types/liver/childhood-liver-cancer

Germ cells are the cells that develop into an embryo and then continue growing into a baby in the womb. Some of these cells remain in the child's  body and may grow into malignant or benign tumours. The most common places these types of tumours appear are the testes, ovaries, at the bottom  of the spine (sacrococcygeal area) and the middle of the brain, chest and abdomen. The different names of these tumours usually refer to the place  where they start. This type of cancer is very rare. The most common one is a yolk-sac tumour and presents with a raised alpha-fetoprotein (a crucial  tumour marker).

Most common symptoms  

Symptoms vary depending on where the tumour is, but usually a lump can be seen and felt in the affected area.

READ MORE 

• Cancer Research UK - What are germ cell tumours? https://cansa.org.za/files/2021/11/Fact-Sheet-on-Germ-Cell-Tumour-of-the-Ovary NCR-2017-web-Nov-2021.pdf 
• NHS England: Germ cell tumours. https://www.nhsinform.scot/illnesses-and-conditions/cancer/cancer-types-in-children/germ-cell tumours/

The neuroectoderm is a layer of cells in the early embryo that give rise to the nervous system. Primitive neuroectodermal tumours (PNETs) are a rare  and aggressive type of childhood cancer that originates from primitive nerve cells in the brain or other parts of the body. They are typically fast-growing  and can spread through the cerebrospinal fluid or other tissues.

Most common symptoms 

Symptoms vary depending on the tumour’s location but can include headaches, vomiting, vision problems, and neurological issues. Treatment often  involves surgery, chemotherapy, and radiation therapy, with outcomes varying based on factors like age and tumour location.  

READ MORE 

• Boston Children's Hospital: What are primitive neuroectodermal tumours? https://www.childrenshospital.org/conditions/primitive neuroectodermal-tumors-pnet 
• Children's Minnesota: What is medulloblastoma or PNET. https://www.childrensmn.org/services/care-specialties-departments/cancer blood-disorders/conditions-and-services/cancer-services/brain-and-spinal-cord-tumor 
  program/medulloblastoma/#:~:text=What%20is%20a%20medulloblastoma?,Organization%20(WHO)%20Classification%20System.
• American Brain Tumour Association: Primitive Neuroectodermal Tumour (PNET). https://www.abta.org/tumor_types/pnet/

Thyroid cancer in children is rare but often diagnosed at a more advanced stage compared to adults. While it can occur at any age, it's more common  in adolescents, especially teenage girls. Fortunately, most children respond well to treatment, with generally better outcomes than adults. Anaplastic  thyroid carcinoma is a rare, highly aggressive, undifferentiated thyroid tumour, accounting for 2% to 3% of all thyroid cancers.

Most common symptoms 

The most common symptoms are a lump in the neck, trouble breathing, trouble swallowing and hoarseness or a change in the voice.

READ MORE 

• Cancer Research UK: Types of thyroid cancer. https://www.cancerresearchuk.org/about-cancer/thyroid-cancer/stages-types/types 
• ENT Health: Pediatric Thyroid Cancer. https://www.enthealth.org/conditions/pediatric-thyroid-cancer/ 

Skin cancer in children is almost always Melanoma. It's the most dangerous kind of skin cancer. It starts in the melanocyte cells that make pigment  (colour) in the skin. It may start as a mole that turns into cancer. Melanoma may spread quickly. Melanoma in children is rare but can occur, with most  cases diagnosed in adolescents between 15 and 19 years old. Early detection is crucial, and any unusual or changing skin growths should be evaluated  by a dermatologist. 

Most common symptoms  

While melanoma in adults often presents as a dark mole, in children, it may appear as a whitish, yellowish, or pink bump or lesion that itches or bleeds.

READ MORE 

• Dermnet: Childhood Melanoma. https://dermnetnz.org/topics/childhood-melanoma 
• MD Anderson Cancer Centre: Childhood Melanoma. https://www.mdanderson.org/cancer-types/childhood-melanoma.html