Leisa J. Ward

Trends in incidence of childhood cancer in Australia, 1983–2006

Background:There are few population-based childhood cancer registries in the world containing stage and treatment data.Methods:Data from the population-based Australian Paediatric Cancer Registry were used to calculate incidence rates during the most recent 10-year period (1997–2006) and trends in incidence between 1983 and 2006 for the 12 major diagnostic groups of the International Classification of Childhood Cancer.Results:In the period 1997–2006, there were 6184 childhood cancer (at 0–14 years) cases in Australia (157 cases per million children). The commonest cancers were leukaemia (34%), that of the central nervous system (23%) and lymphomas (10%), with incidence the highest at 0–4 years (223 cases per million). Trend analyses showed that incidence among boys for all cancers combined increased by 1.6% per year from 1983 to 1994 but have remained stable since. Incidence rates for girls consistently increased by 0.9% per year. Since 1983, there have been significant increases among boys and girls for leukaemia, and hepatic and germ-cell tumours, whereas for boys, incidence of neuroblastomas and malignant epithelial tumours has recently decreased. For all cancers and for both sexes combined, there was a consistent increase (+0.7% per year, 1983–2006) at age 0–4 years, a slight non-significant increase at 5–9 years, and at 10–14 years, an initial increase (2.7% per year, 1983–1996) followed by a slight non-significant decrease.Conclusion:Although there is some evidence of a recent plateau in cancer incidence rates in Australia for boys and older children, interpretation is difficult without a better understanding of what underlies the changes reported.

Population-based survival estimates for childhood cancer in Australia during the period 1997–2006

Background:This study provides the latest available relative survival data for Australian childhood cancer patients.Methods:Data from the population-based Australian Paediatric Cancer Registry were used to describe relative survival outcomes using the period method for 11 903 children diagnosed with cancer between 1983 and 2006 and prevalent at any time between 1997 and 2006.Results:The overall relative survival was 90.4% after 1 year, 79.5% after 5 years and 74.7% after 20 years. Where information onstage at diagnosis was available (lymphomas, neuroblastoma, renal tumours and rhabdomyosarcomas), survival was significantly poorer for more-advanced stage. Survival was lower among infants compared with other children for those diagnosed with leukaemia, tumours of the central nervous system and renal tumours but higher for neuroblastoma. Recent improvements in overall childhood cancer survival over time are mainly because of improvements among leukaemia patients.Conclusion:The high and improving survival prognosis for children diagnosed with cancer in Australia is consistent with various international estimates. However, a 5-year survival estimate of 79% still means that many children who are diagnosed with cancer will die within 5 years, whereas others have long-term health morbidities and complications associated with their treatments. It is hoped that continued developments in treatment protocols will result in further improvements in survival.

Differentials in Survival for Childhood Cancer in Australia by Remoteness of Residence and Area Disadvantage

Background: It is not known whether improvements in cancer survival over recent decades have benefited children from different geographic locations equally. This is the first study to produce national survival estimates for childhood cancer in Australia by remoteness of residence and area-based socioeconomic status. Methods: The study utilized population-based data from the Australian Paediatric Cancer Registry for children diagnosed with cancer from 1996 onward who were at risk of mortality between January 2001 and December 2006 (n = 6,289). Remoteness was specified according to the Australian Standard Geographical Classification Remoteness Areas, whereas an index of area disadvantage was obtained from census information. Five-year relative survival estimates were produced by the period method for all cancers and the most common diagnostic groups, with corresponding age–sex adjusted mortality hazard ratios calculated using Poisson regression. Results: Overall, children with cancer from remote/very remote areas had a significantly lower survival rate than their counterparts in major cities (HR = 1.55, 95% CI = 1.08–2.23). Survival was also lower for children with leukemia living in inner regional (HR = 1.52, 95% CI = 1.11–2.08) or outer regional areas (HR = 1.53, 95% CI = 1.03–2.28). There was weak evidence (Pgrad = 0.051) of a trend toward poorer survival by greater area disadvantage for all childhood cancers. Conclusions: Some variation in prognosis by place of residence was present for children with cancer in Australia, particularly among leukemia patients. Impact: Treatment, clinical or area-related factors that contribute to these survival differentials need to be identified. Cancer Epidemiol Biomarkers Prev; 20(8); 1649–56. ©2011 AACR.

Childhood cancer mortality in Australia

AIM To determine current rates of childhood cancer mortality at a national level for Australia and to evaluate recent trends. METHODS Using population-based data from the Australian Paediatric Cancer Registry, we calculated cancer-related mortality counts and rates for the 3-year period 2006-2008 and trends between 1998 and 2008 by sex, age group, and cause of death (defined according to the International Classification of Childhood Cancers, third edition). Rates were directly age-standardised to the 2000 World Standard Population, and linear regression was used to determine the magnitude and significance of trends. The standardised mortality ratio for non-cancer deaths among children with cancer was also estimated. RESULTS A total of 282 children (23 per million per year) died from cancer in Australia between 2006 and 2008. Large decreases were observed in cancer mortality rates over the study period, particularly for boys (-5.5% per year; p<0.001), children aged 10-14 years old (-5.5% per year; p=0.001), and leukaemia patients (-9.4% per year; p<0.001). However, there was no significant change in mortality due to tumours of the central nervous system. Children with cancer were twice as likely to die from non-cancer causes compared to other children (SMR=2.06; p=0.001). CONCLUSIONS While ongoing improvements in childhood cancer mortality in Australia are generally encouraging, of concern is the lack of a corresponding decrease in mortality among children with certain types of tumours of the central nervous system during the past decade. The results also highlight the need for intensive monitoring of childhood cancer patients for other serious diseases that may subsequently arise.

Area‐based differentials in childhood cancer incidence in Australia, 1996–2006

International studies examining the association between the incidence of childhood cancer and characteristics of the area in which the patient lives have generally reported inconsistent patterns. Area‐based differentials in childhood cancer throughout Australia have not been previously published at a national level.

Cancer incidence and mortality in Indigenous Australian children, 1997–2008

We report cancer incidence and mortality among Indigenous children in Australia and compare the results with corresponding data for non‐Indigenous children. This information is important in understanding the overall burden of cancer in this population, and where disparities exist, to plan what action is required. Age‐standardized rates, and indirectly standardized incidence and mortality ratios (SIRs and SMRs) were calculated for the years 1997–2008. There were 224 cancers identified among Indigenous children (99.5 per million per year) and 52 Indigenous children died from cancer during the study period (22.9 per million per year). The SIR for all cancers was 0.64 (95% CI = 0.56–0.73; P < 0.001) while the SMR was 0.81 (95% CI = 0.61–1.07). These results provide a baseline with which to monitor cancer among Indigenous children over time. Pediatr Blood Cancer 2013; 60: 156–158.