Temporal Changes in Childhood Cancer Incidence and Survival

What is known?

“Stage” is a term describing the extent of cancer spread at the point of diagnosis.  It usually gives a good indication of how likely it is that a patient will survive.

However, the use of different and inconsistent staging systems has been a challenge for research, particularly when looking at childhood cancers. Even though we already know that children diagnosed with cancer today are surviving longer compared to the past, it wasn’t clear how the stage at which cancer was diagnosed affected the outlook or prognosis for the child.

What is new?

The Australian Childhood Cancer Registry has been collecting and cataloguing the stage at diagnosis for patients within a consistent set of staging systems known as the “Toronto Guidelines”. These guidelines are specific to several types of childhood cancer and by using this information, we have been able to compare children diagnosed between 2000-2008 against those diagnosed between 2009-2017.

For most types of childhood cancer, there were no significant changes over time in the stage at which they were diagnosed. However, two exceptions were noted:

  1. For retinoblastoma (a type of eye cancer), there was an increase in the percentage of children diagnosed at “stage 0,” which means the cancer hadn’t advanced to the point where the eye needed to be surgically removed.
  2. For hepatoblastoma (a type of liver cancer), there was an increase in the percentage of diagnosed with “distant spread,” meaning the cancer had already spread to other parts of the body (metastatic disease) at the time of diagnosis.

Our research also found that survival rates for certain late-stage childhood cancer have improved among children diagnosed more recently. This includes cancers such as metastatic medulloblastoma, neuroblastoma, and rhabdomyosarcoma. In the past, these cancers had a poor prognosis, but children diagnosed with these advanced cancers now have a much better chance of survival.

What does this mean?

This study is the first of its kind anywhere in the world to report changes over time in the stage-specific incidence for a variety of childhood cancers.

For retinoblastoma, the shift towards lower stage disease reflects a move toward treatments that preserve the eye. In contrast, the increase in hepatoblastoma patients diagnosed at the metastatic stage is likely due to improvements in medical imaging technology.

The improved survival rates for some types of advanced childhood cancer are likely due to a range of factors, such as new and improved treatments and better supportive care. However, some aspects of our results are not easily explained, and further research is needed to determine why survival for some advanced types of childhood cancers has improved.

Continued adoption of the Toronto Guidelines by cancer registries in other countries will open the way for more precise international comparisons to be made. This will help researchers to identify where survival rates for childhood cancer have improved the most as well as where the greatest gains in survival may occur in the future.

Contact: Danny Youlden

Reference:Youlden DR, Baade PD, Frazier AL, et al. Temporal changes in childhood cancer incidence and survival by stage at diagnosis in Australia, 2000-2017. Acta Oncologica. 2023 doi: 10.1080/0284186X.2023.2251668.