Childhood cancer stage at diagnosis and survival
Introduction
Australia has collected 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). Cancer Australia has now published updated national data on childhood (paediatric) cancer stage at diagnosis for 16 major childhood cancer types diagnosed in 2006-2014 for children aged 0-14 years. The initial release of these data in 2018 represented the first time in the world that national level data on stage at diagnosis and survival was reported for these childhood cancers. These data were collected under the Australian Government’s Investing in Medical Research - Fighting Childhood Cancer measure, from a world first trial of the Toronto Paediatric Cancer Stage Guidelines to determine stage at diagnosis for childhood cancers1. The Guidelines and associated Business Rules used to collect these data are now endorsed internationally 2, 3.
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.
The 16 cancer types for which data are reported represent approximately three-quarters of all childhood cancers diagnosed in Australia and other high-income countries1 – the relative proportions of all incident childhood cancers diagnosed in 2006–2014 are summarised in Figure 1. For each of the 16 major childhood cancer types, stage at diagnosis is reported using a tiered system as follows:
- Tier 1: A less-detailed staging system for registries with limited resources; and
- Tier 2: A more-detailed staging system for well-resourced registries. Tier 2 stage categories can be collapsed to the Tier 1 categories to enable comparisons of data from different registries.
Some cancer types have the same stage categories for both the Tier 1 and Tier 2 criteria. Where there are differences in the Tier 1 and Tier 2 stage categories, the results for these Tiers are presented separately in the text with common groupings of ‘limited’ and ‘advanced’ stage provided, where relevant.
The childhood cancer stage data and five-year relative survival data reported for these measures were collected and analysed by the Cancer Council Queensland, with the involvement of all state and territory population-based cancer registries and major paediatric hospitals, 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 measures:
- Distribution of childhood cancer stage
- Five-year relative survival by stage at diagnosis for childhood cancers
The 16 childhood cancer types reported on the NCCI website are as follows:
| Cancer type | 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 tissues around bones |
| Hepatoblastoma | Liver |
| Hodgkin lymphoma | Lymphatic system/ lymphocytes |
| Medulloblastoma and other central nervous system (CNS) embryonal tumours | Brain and central nervous system |
| Neuroblastoma | Sympathetic nervous system |
| Non-Hodgkin lymphoma | Lymphatic system/ lymphocytes |
| Non-rhabdomyosarcoma soft tissue sarcoma | Soft tissues |
| Osteosarcoma | Bone or soft tissues around bones |
| Ovarian cancer | Ovary |
| Retinoblastoma | Eye |
| Rhabdomyosarcoma | Soft tissues |
| Testicular cancer | Testis |
| Wilms tumour | Kidney |
*Groupings have been adapted from the International Classification of Childhood Cancers, 3rd edition (ICCC-3) Diagnostic Groups
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 16 major childhood cancers
A high proportion of cases for the 16 major childhood cancer types could be staged overall using the Tier 1 (95%) or Tier 2 (94%) staging criteria. The proportion of cases staged for each cancer type using the Tier 1 criteria ranged from 85% (for acute myeloid leukaemia) to 99% (for retinoblastoma). Using the more detailed Tier 2 criteria, the proportion of cases staged ranged from 84% (for non-rhabdomyosarcoma soft tissue sarcoma) to 98% (for ovarian cancer and retinoblastoma).
Of the 16 cancer types, acute lymphoid leukaemia was the most commonly diagnosed childhood cancer
Acute lymphoid leukaemia was the most commonly diagnosed childhood cancer, representing 25% of all childhood cancer cases diagnosed in the period 2006−2014.
A high proportion of cases were diagnosed at a limited stage for most of the major childhood cancer types
For 12 cancer types the majority of cases were diagnosed at a ‘limited’ stage before the cancer had spread to other parts of the body. Of these cancer types, the proportion of cancers diagnosed at a limited stage ranged from 64% for hepatoblastoma to 98% for retinoblastoma using the Tier 1 criteria. Using the more detailed Tier 2 criteria, this ranged from 64% of cases for hepatoblastoma to 97% of cases for retinoblastoma.
For Hodgkin lymphoma and neuroblastoma, a relatively high proportion of cases were diagnosed at an advanced stage
Advanced stage cancers accounted for 46% of cases for Hodgkin lymphoma (IIIA/IIIB: 19%, IVA/IVB: 27%) and 55% of cases for neuroblastoma (metastatic or M: 49%, MS: 6%).
For cancers of the blood and bone marrow, a majority of cases had no central nervous system involvement
Most children diagnosed with acute lymphoid leukaemia (86%) or acute myeloid leukaemia (56%) were classified as having no central nervous system involvement (CNS-).
Childhood cancers diagnosed at a ‘limited’ stage generally had higher relative survival rates than those diagnosed at an ‘advanced’ stage
For four cancer types, five-year relative survival for advanced cancers was not examined due to small numbers
Five-year relative survival was not examined for advanced stage ependymoma, retinoblastoma, testicular cancer and ovarian cancer.
For ten cancer types, five-year relative 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 nine cancer types, children diagnosed at a limited stage had statistically significant higher survival than those diagnosed at an advanced stage. These cancer types included acute lymphoid leukaemia, Ewing sarcoma, hepatoblastoma, medulloblastoma, neuroblastoma, non-rhabdomyosarcoma soft tissue sarcoma, osteosarcoma, rhabdomyosarcoma, and Wilms tumour.
For non-Hodgkin lymphoma, survival was also higher for children with limited stage disease (limited: 92%; stage I: 97%, stage II: 97%, stage III: 89%) compared to survival of those with advanced stage disease (advanced or stage IV: 85%), but these differences were not statistically significant.
Five-year relative survival was similar regardless of stage at diagnosis for acute myeloid leukaemia
There was no statistically significant difference in five-year relative survival by stage at diagnosis for acute myeloid leukaemia (77% for CNS-, and 78% for CNS+).
Five-year relative survival is high for Hodgkin lymphoma regardless of stage at diagnosis
For children diagnosed with Hodgkin lymphoma, survival was high (at least 97%) 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 relative survival was lower than 50% for children diagnosed with advanced medulloblastoma and other CNS embryonal tumours (metastatic: 44%; M1/M2: 47%, M3: 43%), non-rhabdomyosarcoma soft tissue sarcoma (metastatic or stage IV: 46%), and osteosarcoma (metastatic: 37%).
Figure 1: Proportional incidence of childhood cancers, and relative stage distribution and five-year relative survival by stage at diagnosis for the three most common childhood cancer types, 2006–2014
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. 2018. Assessing the feasibility and validity of the Toronto Childhood Cancer Stage Guidelines: a population-based registry study. The Lancet Child & Adolescent Health, 2(3): p. 173-179.
2. Brierley, J., Gospodarowicz, M., and Wittekind, C. 2016. The TNM Classification of Malignant Tumours, 8th edition. Lyon, France: Union for International Cancer Control (UICC).
3. International Association of Cancer Registries 2019. Paediatric Cancer Stage Guidelines - The IACR endorses the published Toronto Childhood Cancer Stage Guidelines and associated staging rules for use by population-based cancer registries.; Available from: <http://www.iacr.com.fr/index.php?option=com_content&view=article&id=153&Itemid=657>.
