Paediatric Haematology and Oncology

 



Q1. What types of patients are under the care of Paediatric Haematology and Oncology?
Paediatric haematology and oncology is primarily taking care of children below 18 years of age. Our blood is composed of various blood cells, such as red blood cells, platelets and white blood cells. Haematological and oncological diseases may arise when red blood cells or platelets are in excess or deficient. The conditions can be benign or malignant. Our blood also contains clotting proteins, and any related disorder such as haemophilia also falls under the case of same specialty of paediatric haematology and oncology.
 
Tumour type is highly variable as they can occur in any organ. Either benign or malignant, a tumour may arise due to abnormal cell growth in a specific organ. Lymphoma, neuroblastoma and different forms of brain tumours are common in children.
 
Q2. What are the differences in the same specialty of blood or cancer between adults and children?
The biggest difference lies in the conditions managed by each specialty. Adult haematologist deals with benign and malignant blood related disorders. The former includes anaemia, thrombocytopenia, etc. and the latter leukaemia, lymphoma, etc. Due to the large case load, solid tumours in adults are often managed by other specialists. Given the relatively small case load, both blood disorders and solid tumours in children are managed by specialists in paediatric haematology or oncology.
 
Treatment for paediatric cases is also notably different from that in adult cases.  In adults, solid tumours mostly originate from pathological changes in epithelial or glandular tissues, such as lung cancer, colorectal cancer, breast cancer, etc. All these tumours are attributable to abnormalities in epithelial or glandular tissues. The solid tumours in children are different: they mostly arise from pathological changes of primitive or embryonic cells during development. These tumours are thus commonly known as blastomas as they originate from cells in early stage of development that became abnormal. Blastomas are chararcterised by rapid growth and often respond favourably to treatment. The cure rate of child cancers is generally higher than that of adult cancers, i.e. up to 70 to 80% of children with cancers survive.  
 
Q3. What are the common blood disorders in children in Hong Kong?
In Hong Kong, common benign blood disorders in children include immune-mediated thrombocytopenia, various types of anaemia such as iron deficiency anaemia or haemolytic anaemia, and thalassaemia, which is prevalent in Southeast Asia. There are also different types of blood disorders that can affect the clotting factors, such as haemophilia. The most common malignant blood disorder in children is acute lymphoblastic leukaemia. Lymphocytes are one form of white blood cell. Pathological changes may also arise in other types of white blood cells, such as myeloid cells found in acute myeloid leukaemia.
 
Q4. What types of tumours are common among local children?
Like blood disorders, tumours can be classified as either benign or malignant. Malignant paediatric tumours are most commonly found in the brain with different subtypes, such as gliomas, or tumours originating from embryonal neural tissues such as medulloblastomas, etc. Cancer can also arise from pathological changes in the primary tissues of every single organ, such as kidneys, liver, adrenal glands, etc.
 
Q5. What are benign tumours? How can they affect children?
There are several types of benign tumours. The simplest form is infantile haemangioma, which is common in infants. While it is believed to disappear spontaneously, it is found in the head and face in 80% of cases which may impact on the appearance. Instead of complete disappearance, it may leave behind scar-like tissues. Proactive treatment is therefore encouraged and often effective. Certain other types of benign tumours such as those originating from soft or fibrous tissues may recur from time to time. Benign tumours are highly variable as well. They are managed by separate clinics, for conditions such as vascular malformations and benign tumours in blood vessels in my previous practice. Abnormal tissue over growth is not a malignancy. It can now be treated effectively with targeted therapy.
 
Q6. Which are malignant tumours? What types of children are most susceptible to them? How are they managed?
As we have mentioned earlier, many brain tumours in children are malignant. Three types of malignant brain tumours are common among children in China. The first one is glioma. The second type is medulloblastoma. It originates from embryonic tissues, and usually occurs in the cerebellum. The third one is germ cell tumour. It is particularly prevalent among Chinese or East Asians such as Japanese or Korean. In most cases, all these tumours are highly treatable. For example, the cure rate of germ cell tumours is over 90%. For medulloblastoma, it is around 70 to 80%. The cure rate of glioma depends on the pathological grading, with the low-grade at over 90% but high grade remains difficult to treat. So even for children with malignant tumour, it is far from hopeless.
 
There are also various types of solid tumours from various organs, such as hepatoblastoma and nephroblastoma, and cure is highly probable. Some tumours are more challenging, such as neuroblastoma. But thanks to advancement of treatment methods, the cure rate has improved significantly in recent years. Recent advances such as proton therapy, systemic nuclear medicine, immunotherapy have greatly increased the cure rates of various types of malignant tumours with fewer side effects than conventional treatments such as chemotherapy.

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