Feature: Childhood cancer stage at diagnosis (first release)
Introduction
Australia has had high quality data on cancer incidence, mortality and survival over many years through the efforts of state and territory cancer registries, and the Australian Institute of Health and Welfare (AIHW). Until now national data on childhood (paediatric) cancers ‘stage at diagnosis’ (that is, the extent to which a cancer has spread when first diagnosed) has not been available. Stage at diagnosis is categorised in order of increasing severity, and different childhood cancer types have different staging systems. To date, there has been no universally accepted system for staging childhood cancers and, as such, there are multiple systems in clinical use.
The lack of nationally consistent childhood cancer staging data has been an identified gap in Australia and internationally. Knowing the distribution of stage at diagnosis and outcomes by stage is crucial to understanding variations in survival, and can help inform further research and targeted cancer control strategies to reduce the proportion of cancers diagnosed at an advanced stage.
Under the Australian Government’s Investing in Medical Research - Fighting Childhood Cancer measure, initial national data have been reported about childhood cancer stage at diagnosis for sixteen major childhood cancers from 2006-2010 for children aged 0-14 years.
Australia is the first country in the world to report national stage at diagnosis data and five-year survival outcomes for these childhood cancers.
The sixteen cancer types for which data are reported represent approximately three-quarters of all childhood cancers diagnosed in Australia1 – the relative proportions of all incident childhood cancers are summarised in Figure 1. These are initial data and more complete information will be made available when the collection of data for 2006-2014 is finalised in 2019. The childhood cancer stage data and five-year observed survival data reported for this indicator were collected and analysed by the Cancer Council Queensland, with the involvement of all state and territory population-based cancer registries, as part of a project funded by Cancer Australia.
A detailed examination of the data, including information about the collection methodology, data sources, and guidance for interpretation are available in the following indicator pages:
- Distribution of childhood cancer stage
- Five-year observed survival by stage at diagnosis for childhood cancers
The 16 childhood cancer types reported on the NCCI website are as follows:
| Type of cancer | Broad tissue of origin |
| Acute lymphoid leukaemia | Blood and bone marrow |
| Acute myeloid leukaemia | Blood and bone marrow |
| Ependymoma | Brain and central nervous system |
| Ewing sarcoma | Bone, or soft tissue around bones |
| Hepatoblastoma | Liver |
| Hodgkin lymphoma | Lymphatic system/ lymphocytes |
| Medulloblastoma | Brain and central nervous system |
| Neuroblastoma | Nervous system |
| Non-Hodgkin lymphoma | Lymphatic system/ lymphocytes |
| Non-rhabdomyosarcoma soft tissue sarcoma | Soft tissues of the body |
| Osteosarcoma | Bone |
| Ovarian cancer | Ovary |
| Retinoblastoma | Eye (retina) |
| Rhabdomyosarcoma | Soft tissues of the body |
| Testicular cancer | Testis |
| Wilms tumour | Kidney |
For more information about childhood cancer, please refer to Cancer Australia’s Children’s Cancer website. More data on childhood cancer in Australia can be found at the Cancer Council Queensland’s Australian Childhood Cancer Statistics Online website.
A high proportion of childhood cancers were staged and most cancers were diagnosed at a limited stage
Staging completeness was high overall for each of the sixteen major childhood cancers
A high proportion of cases for the sixteen major childhood cancer types were able to be staged overall (94%). The proportion of cases staged for each cancer type ranged from 87% (for acute myeloid leukaemia) to 98% (for retinoblastoma and hepatoblastoma).
A high proportion of cases were diagnosed as limited stage cancers for most of the major childhood cancer types
For twelve of the sixteen childhood cancer types, the majority of cases were diagnosed at a limited stage, ranging from 63% of cases for medulloblastoma and other CNS embryonal tumours to 95% of cases for retinoblastoma.
For Hodgkin lymphoma and neuroblastoma, a relatively high proportion of cases were diagnosed at an advanced stage
Advanced stage (metastatic) cancers accounted for the highest proportion of cases diagnosed for Hodgkin lymphoma (IVA/IVB, 34%) and neuroblastoma (45%) .
For cancers of the blood and bone marrow, a higher proportion of cases had no central nervous system involvement
Most children diagnosed with acute lymphoid leukaemia (86%) or acute myeloid leukaemia (55%) were classified as having no central nervous system involvement (CNS-).
Childhood cancers diagnosed at a limited stage generally had higher observed survival rates that those diagnosed at an advanced stage.
For 12 cancer types, five-year observed survival was higher if the cancer was diagnosed at a limited stage, or before the cancer had spread to other parts of the body (including CNS-)
For seven of the sixteen childhood cancer types, children diagnosed at a limited stage had a significantly higher five-year observed survival than those diagnosed at an advanced stage. These cancer types were medulloblastoma, neuroblastoma, non-rhabdomyosarcoma soft tissue sarcoma, osteosarcoma, rhabdomyosarcoma, Wilms tumour, and acute lymphoid leukaemia.
For five cancer types, five-year observed survival was also higher for limited stage cancers but these were not statistically significant. These cancers were Ewing sarcoma, hepatoblastoma, ovarian and testicular cancer combined, and non-Hodgkin lymphoma.
Five-year observed survival was similar regardless of stage at diagnosis for acute myeloid leukaemia
There was no significant difference in five-year observed survival by stage at diagnosis for acute myeloid leukaemia, with five-year observed survival of 76% and 79% for children with CNS- and CNS+ cancers, respectively. For retinoblastoma and ependymoma, comparisons of survival by stage at diagnosis were not possible due to the small number of advanced stage cancers.
Five-year observed survival is high for Hodgkin lymphoma regardless of stage at diagnosis
For children diagnosed with Hodgkin lymphoma, five-year observed survival was 100% regardless of stage at diagnosis.
Some cancer types had notably lower survival outcomes when the cancer was diagnosed at an advanced stage (metastatic).
Five year observed survival was lower than 50% for children diagnosed with metastatic medulloblastoma (44%), non-rhabdomyosarcoma soft tissue sarcoma (40%), osteosarcoma (30%), or rhabdomyosarcoma (47%).
Figure 1: Relative proportions of all incident childhood cancer cases diagnosed in 2006-2010, for sixteen major cancer types
Note: Click on the image above to expand
References
1. Aitken, J.F., Youlden, D.R., Moore, A.S., Baade, P.D., Ward, L.J., Thursfield, V.J., Valery, P.C., Green, A.C., Gupta, S., and Frazier, L.A., Assessing the feasibility and validity of the Toronto Childhood Cancer Stage Guidelines: a population-based registry study. The Lancet Child & Adolescent Health, 2018. 2(3): p. 173-179.
