Childhood is the age where children have a lot of fun, wishes and desires. But for children with cancer, it is battle against the odds. These children are an inspiration in their ability to put aside their pain and sorrow and make the best of whatever life has to offer.
Childhood cancer is the term given to a variety of malignant tumours that occur in children under the age of 16 years. Childhood cancers constitute to 3-4% of all cancers. Every year 250000 children are diagnosed with cancer worldwide. In India, it is estimated that nearly 40000 new childhood cancer cases occur each year. In one of the reports not more than 20000 cases are being diagnosed. Of those diagnosed a good number of cases come in an advanced stage. Around 70% children die of cancer in India despite the high cure rates in developed countries due to lack of awareness, late detection and late diagnosis, inadequate facilities, a high cost of treatment and lack of supportive care.
The common types of childhood cancers are (see figure 1)
Leukaemia (Blood cancer): Leukaemias are cancers of the blood-forming cells of the bone marrow. It accounts for about one-third of all childhood cancers. They are subdivided into acute and chronic, myeloid and lymphatic. Approximately98% of leukaemias are acute in those under 16. Acute lymphatic (lymphoblastic) leukaemia(ALL) accounts for around 75% of all childhood leukaemias, with the highest incidence occurring in those aged 1-4 years.
Brain and Spinal Cord: Brain and spinal cord cancers are the most common type of a solid tumour in children accounting for approximately 20% of all childhood cancers. The two main types of childhood brain tumours are gliomas and medulloblastoma. Gliomas develop in the supporting cells of the brain (which hold the nerve cells in place) and
are subdivided into two main types, astrocytomas(which account for between 30-50% of cases) and ependymomas(which account for approximately 10%). Medulloblastomas usually develop in the cerebellum at the back of the brain and account for25% of childhood brain tumours.
Lymphomas: Lymphomas are cancers of the lymphatic system which typically arise in lymph node tissue, but may also develop in other sites such as bone, stomach, spleen and the small intestine. They are usually divided into two groups, Hodgkin’s disease (which accounts for about 5% of childhood cancers) and Non-Hodgkin’slymphoma (accounting for approximately 7% of childhood cancers). There are two main types of Non-Hodgkin’s lymphoma, B cell which usually involves the lymph nodes in the head, neck, throat and abdomen, and T cell which usually affects lymph nodes in the chest.
Neuroblastoma: Neuroblastoma is a solid tumour of specialised nerve cells(neural crest cells). It can occur anywhere in the sympathetic nervous system but is commonly diagnosed in the adrenal gland. Neuroblastoma accounts for about 8% of childhood cancers with 80% of cases occurring before the age of 4.
Nephroblastoma(Wilms’ tumour): Nephroblastoma is the most common renal (kidney) tumour of childhood accounting for approximately 7% of paediatric cancers, principally in those under 5 years old.
Sarcomas are malignant tumours that arise from mesenchymal tissue (bone, cartilage, connective tissue and muscle). The most common sarcomas of childhood are rhabdomyosarcoma, osteosarcoma and Ewing’s sarcoma.
Rhabdomyosarcomaarises mainly from muscle and is the most common soft tissue sarcoma of childhood. Embryonal rhabdomyosarcoma occurs primarily in the head and neck (40%) or genitourinary tract (20%) of younger children (4-6 years).
Alveolar rhabdomyosarcoma is found most frequently in the trunk and extremities (30%) of older children (>10 years).
Osteosarcoma is a bone tumour that commonly occurs in the arms or legs, accounting for approximately 5% of all childhood cancers.
Ewing’s sarcoma is a small round cell tumour of the bone usually affecting patients aged 10-15 years. It is mainly found in the femur, humerus, pelvic bones and ribs and is extremely malignant with metastasis at diagnosis in 90% of patients.
Retinoblastoma: Retinoblastoma is a malignant eye tumour occurring in the retina that accounts for 2% of all paediatric cancers. A tumour may be present at birth due to a strong hereditary tendency and usually presents in children under 3 years old.
Other: Other childhood tumours include germ cell tumours, hepatic (liver) tumours and rare tumours.
Causes of cancer in children
Parents often worry that something they did or didn’t do may have caused their child’s cancer. This is not the case, so you shouldn’t feel guilty or that you’re to blame for your child’s illness. It’s very rare for another child in a family to develop cancer, as most cancers aren’t caused by an inherited faulty gene and so it is usually not necessary to investigate siblings. Cancer is not infectious and can’t be passed on to anyone who comes into contact with your child.
Although we have identified a number of lifestyle changes that can help to prevent many adults from developing cancer, we don’t know how to prevent most childhood cancers. We don’t know what causes childhood cancers either. We do know some factors that increase risk, but most children with cancer don’t have any of these risk factors. And many children who do have risk factors won’t go on to develop cancer.
The known risk factors include
- Inherited medical conditions(Downs syndrome, Neurofibromatosis, Klinefelter’s syndrome)
- Family history/Genes (Retinoblastoma, Li-Fraumeni syndrome)
- Problems with development in the womb
- Exposure to infections (Epstein Barr Virus EBV,
- Exposure to radiation
- Previous cancer treatments
Symptoms of cancer in children
As mentioned above there are many different types of cancers and their symptoms vary depending on the type, stage of cancer and the age of the child. The symptoms `vary among children. If your child has a symptom we haven’t included here, and it hasn’t gone away after a few weeks, take them to the paediatrician. The following symptoms are not usually cancer, but see your doctor if your child has any of these
- Not able to pass urine, or blood in urine
- An unexplained lump or firmness or swelling anywhere in the body
- Swollen glands
- Back pain that doesn’t go away
- Persistent headaches
- Frequent bruising
- Feeling tired all the time
- Unexplained fits (seizures) or changes in vision or behaviour
- Abdominal pain or swelling all the time
- Unexplained vomiting
- Unexplained sweating or fever
- Unexplained weight loss or poor appetite
- Changes in the appearance of the eye or unusual eye reflections in photos
- Frequent infections or flu-like symptoms
For most childhood cancers tissue biopsy is needed to confirm a diagnosis. For leukaemia, lymphoma or neuroblastoma a bone marrow aspiration and biopsy may be taken. X-rays, CT (computerised tomography), MRI (magnetic resonance imaging) and ultrasound scans may be used to identify most childhood tumours and establish the extent of any disease. For suspected leukaemia, lymphoma or retinoblastoma a lumbar puncture (spinal tap) may be performed to determine whether the fluid surrounding the
brain and spinal cord (cerebrospinal fluid) contain cancerous cells. Blood tests may help determine the extent of any disease and for a diagnosis of abnormal genes in retinoblastoma. A urine test may show the presence of VMA(vanillyl mandelic acid) or HVA (homovanillic acid) which are increased in more than 90% of neuroblastoma patients. Nuclear medicine scans such as MIBG(meta-iodo-benzyl guanidine) scans may show the location of a neuroblastoma whereby the tracer is selectively taken up by catecholaminergic cells
The stage of cancer describes the extent of a disease and is important in terms of planning treatment and indicating prognosis. There are various staging classifications relating to the site of a tumour but the TNM (a tumour, nodes, metastasis) system is the most widely used for solid tumours. In general, stage 1 shows cancer confined to the primary organ. This lesion tends to be operable and completely resectable. Prognosis for this stage cancer is usually good. Stage 4 tumours show evidence of distant metastases beyond the site of origin. Survival rates are lower in higher stage cancers compared to early-stage cancers. Bone and PET(Positron Emission Tomography)-FDGscans help us to find out the extent of spreading the disease.
Because of the rarity of paediatric cancers, children are referred to specialist centres for their treatment. The treatment received varies with each individual depending on factors such as tumour site, stage and the child’s general health.
In the 1960s only about 3 out of every 10 children (30%) with cancer were successfully treated. But in the past 40 years of treatment for children with cancer has improved greatly. Now more than 8 out of every 10 children diagnosed with cancer will live for at least 5 years. Most of these children will be cured. For some types of childhood cancer such as acute lymphoblastic leukaemia (ALL) and Wilms’ tumour (a type of kidney cancer in children), this rate is even higher. With these types of cancer, more than 8 out of 10 children (80%) diagnosed will live for at least 5 years. Hodgkin lymphoma and an eye cancer called retinoblastoma are curable in more than 9 out of 10 children (90%). Even though cancer is not common in children; it is one of the important cause of death in children.
- FACTS OF CHILDHOOD CANCER
- The incidence of childhood cancer is on the rise
- The average age at diagnosis is 6 years old
- Childhood cancer is not one disease, there are 16 major types of pediatric cancers and over 100 subtypes
- Unlike the cause of adult cancers, the causes of most childhood cancers are unknown. At present, childhood cancer cannot be prevented
- Survival rates can range from almost 0% for cancers such as Diffuse Intrinsic Pontine Glioma, a type of brain cancer, to as high as 90% for the most common type of childhood cancer known as Acute Lymphoma Leukemia (ALL).
- The average 5-year survival rate for childhood cancers when considered as a whole is 83%.
- Children with cancer often have a more advanced cancer when first diagnosed
- The majority (70-90%) of childhood cancer is curable because of the better response to the treatment and protocols
- In India, it is estimated that nearly 40-50,000 new childhood cancer cases present each year
- In India, as in adult cancers, 70% children with cancer still die of the disease in India due to lack of awareness, late detection and diagnosis, inadequate pediatric cancer treatment facilities, the exorbitant cost of treatment and lack of supportive care.
Although about 8 out of 10 children are now successfully treated, childhood cancer is still devastating for everyone concerned. Treatment can last for months, or even years, which means longer stays in hospital and being away from the home, school, friends and siblings. In India, we do not have facilities for children to do school work under the guidance of teachers in the hospital wards. Many of the times children may feel like not doing anything at times, except having a cuddle with mum or dad. As we make progress in reducing infection-related childhood deaths in India, it is no longer acceptable to ignore children with cancer, who have an increased likelihood of cure with appropriate treatment. Early diagnosis, multidisciplinary team management, appropriate response assessment and following the evidence-based medicine practice will improve these children’s ability to fight cancer.
Dr Harsha Prasada L
MD, DCH, DNB, MRCPCH(London), CCT (London)
Consultant Paediatric Haematologist and Oncologist, Special interest in primary immunodeficiency disorders.
KMC Hospital Mangalore 575001