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What is Cancer?
Cancer afflicts about one in 550 children under the age of 15 years and over 150 new cases are diagnosed each year in New South Wales. Acute leukaemia (including lymphoblastic and non-lymphoblastic types) is the commonest, representing 35% of all childhood malignancies.Other common cancers include:
- Central nervous system
(brain and spinal cord) tumours, 17%;
- Lymphomas or tumours of
lymphatic tissue, including Hodgkin's Disease and Non-Hodgkin's lymphoma,
11%;
- Neuroblastoma and Neural
Crest Tumours involving the adrenal gland or "sympathetic" nervous tissue,
8%;
- Wilms' (kidney) Tumour;
7%;
- Rhabdomyosarcoma and Soft
Tissue Sarcomas, 5%.
Rarer tumours include germ cell tumours, liver tumours (Hepatoblastomas) and eye tumours (Retinoblastomas). Some tumours, may occur in many parts of the body, while in other instances the primary tumour always originates in a particular organ (such as brain and kidney tumours).
Assessment of children with cancer
A combination of clinical
evaluation, laboratory and imaging techniques is usually necessary to provide
the most satisfactory assessment of a tumour. Clinical and pathological
staging is important for deciding on treatment and predicting outcome.
For most solid tumours there are several stages (usually four); Stage I
usually implies a very localised and removable primary tumour, Stages II
and III are intermediate, and Stage IV indicates distant spread of the
tumour with metastases or secondaries. Patients with Stage IV disease have
a more serious outlook and generally require more intensive treatment than
those with Stage I disease.
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The microscopic
pathology (histology) of the tumour is also important; for example, there
are subtypes of Leukaemia, Lymphoma, Wilms' Tumour and most other tumours.
Some of these subtypes are less aggressive than others.
The age of the patient is another factor to consider. In Neuroblastoma with metastases the outlook is far better in an infant less than one year than in a child over the age of two years. On the other hand, lymphoblastic leukaemia in a young infant has a much more serious outcome than in a child aged two to nine years. |
Three major forms of treatment may be used to treat childhood cancers, usually in combination. They are surgical removal, radiotherapy and chemotherapy. Complete or even partial removal of the tumour is very valuable in localised solid cancers. Radiotherapy is often used to treat the tumour bed in order to eradicate cancer cells remaining in that area. It may also be used to treat tumours where removal by operation is not possible or not indicated, such as leukaemic infiltration around the brain. Chemotherapy or drug treatment is used to "mop up" any stray cancer cells after removal of the primary tumour, or to treat known widespread disease. For certain tumours differing combinations may be used. For example, in Wilms' Tumour surgical removal, local radiotherapy and chemotherapy are combined, while in osteogenic (bone) sarcoma operation is combined with chemotherapy, but usually no radiotherapy, and in leukaemia chemotherapy is used with irradiation of the central nervous system, but without surgical procedures, and in lymphomas chemotherapy is commonly used alone. Supportive measures with transfusions of blood and platelets, with antibiotics for infections, and intravenous fluids for nutrition may be required. Psychosocial support by the members of staff is expected to be given to all patients and families.
Outcome of children with cancer
Over the past 15 to 18 years
there has been a marked improvement in the long term survival and cure
rate in childhood cancer. In the early 1960's there were virtually no cures
for leukaemia, and the long term survival for other cancers was low. By
1975 50% of childhood malignancies were curable, and has been steadily
increasing since then.
Table I below illustrates the expected cure rates for different types of childhood cancer in 1970, 1975, 1985 and 1995. There are steady and sometimes dramatic improvements over these periods. The results do not include the additional benefits and cures now obtained with bone marrow transplantation, especially in leukaemia and neuroblastoma. Table II shows the cure rates for tumours with widespread disease (Stage IV) at diagnosis. Many of these tumours have over 50% chance of cure. The dramatic effect of age on the outcome of neuroblastoma is indicated in the table.
Cure implies that the cancer will not recur and that usually a normal lifespan can be expected. Some patients who have had recurrences of disease can be re-treated successfully and be eventually cured of their disease.
It is estimated that by the
end of this century, the patients cured of cancer will represent one in
1,000 adults. It is hoped that these figures will rise further. In the
meantime, it is important that patients previously treated for cancer will
continue to be followed and seen at intervals at long-term follow-up clinics.
| Table 1. Cure rates in various types of cancer in children | ||||
| 1970 | 1980 | 1985 | 1995 | |
| Acute Lymphoblastic Leukaemia* | 40% | 50% | 70% | 72% |
| Acute Non-Lymphoblastic Leukaemia* | 15% | 20% | 35% | 40% |
| Hodgkin's Disease | 50% | 65% | 80% | 85% |
| Non-Hodgkin's Lymphoma | 30% | 50% | 70% | 70% |
| Neuroblastoma* | 35% | 35% | 40% | 40% |
| Wilms' Tumour | 70% | 70% | 80% | 85% |
| Rhabdomyosarcoma and Soft Tissue Sarcoma | 40% | 50% | 65% | 70% |
| Osteogenic Sarcoma | 10% | 40% | 70% | 70% |
| Ewing's Sarcoma | 30% | 45% | 50% | 60% |
| Hepatoblastoma | <5% | 10% | 40% | 40% |
| Overall | 50% | 60% | 65% | 70% |
| * Does not include the additional benefit of bone marrow transplants. | ||||
Table 2. Cure rates in widespread (metastatic) cancer in children
Acute Lymphoblastic Leukaemia*
70%
Acute Non-Lymphoblastic
Leukaemia* 35%
Non Hodgkin's Lymphoma Stage
IV 70%
Hodgkin's Disease Stage
IV 60%
Wilms' Tumour Stage IV 65%
Neuroblastoma Stage IV
If aged less than 1 year
80%
If aged over 2 years <5%
*Note: Does not include
the additional cures obtained after bone marrow transplantation.
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