Updating sarcoma reporting

Cancer data commentary no. 7

Cancer data in Australia (CdiA) now includes the group ‘all sarcomas combined’. Sarcomas are cancers that originate in bone, cartilage and the soft tissues of the body (for example, the ligaments, tendons, muscles, subcutaneous tissue and blood vessels). CdiA already includes data on soft tissue sarcoma and bone cancer and the combination of these produces ‘all sarcomas combined’.

Note that many kinds of cancer that originate outside bones can spread to the bones. However, CdiA only reports on cancers classified by their primary (original) site, not where they spread to (secondary sites). In the context of primary site, the terms “bone cancer” and “bone sarcoma” are equivalent, i.e. every primary cancer of the bone is a sarcoma.

Prior to the creation of this new cancer reporting category, a review was undertaken of the CdiA definitions of soft tissue sarcoma and bone cancer. This resulted in changes to both definitions. This commentary summarises the impact of these changes on the time series of incidence counts.

About the review process

The definitions of soft tissue sarcoma and bone cancer used in previous versions of CdiA were compared with the RARECAREnet project list of cancers. The RARECAREnet project involves partners all around Europe and aims at building an information network to provide comprehensive information on rare cancers to the community at large. The definitions used within the RARECAREnet project and potential changes to them were discussed with Australia’s cancer registries. It should be noted that the potential changes discussed with Australian cancer registries relate only to the cancer coding and not whether the cancer is rare.

Progress of the review

At the time of releasing CdiA, the review is not fully complete. It is possible that some further small changes will occur as work continues in this area. However, the current new definitions already offer a substantial improvement to existing reporting.

Impact of changes

The following sections highlight the impact of the changes to cancer incidence counts. The definitions themselves can be found in Appendix A.

Bone cancer

The impact of using the new definition is very small. Between 2008 and 2017 the new definition gives an average of 2 more cases per year than the old definition.

Figure 1: Cases of bone cancer, old and new definitions, persons, 1982–2017

Figure 1 shows the number of cases of bone cancer diagnosed between 1982 and 2017 and compares the counts of bone cancer when using the previous and revised coding. Between 1982 and 2017, the two different measures align closely over time. The general trend for both is that of slightly increasing counts over time with a sharper increase from 2012.

Notes:

  1. 2017 counts include estimates for the Northern Territory and an estimate of late registrations for all other jurisdictions.
  2. 2016 counts include estimates of late registrations for the Northern Territory only.

Source: AIHW Australian Cancer Database 2017

Soft tissue sarcoma

The impact of using the new definition varies from year to year. Between 2008 and 2017 the new definition gives an average of around 58 more cases per year than the old definition.

Figure 2: Cases of soft tissue sarcoma, old and new definitions, persons, 1982–2017

Figure 2 shows the number of cases of soft tissue sarcoma diagnosed between 1982 and 2017 and compares the counts of soft tissue sarcoma when using the previous and revised coding. The number of cases diagnosed using the previous coding begins at 568 in 1982 and increases to 1,746 in 2017. The number of cases diagnosed using the revised coding changes from 580 in 1982 to 1,803 in 2017. The difference in counts for the respective measures becomes more pronounced from around the year 2000.

Notes:

  1. 2017 counts include estimates for the Northern Territory and an estimate of late registrations for all other jurisdictions.
  2. 2016 counts include estimates of late registrations for the Northern Territory only.

Source: AIHW Australian Cancer Database 2017


Appendix A

The definitions are given in terms of ICD-O-3 topography and histology codes. The RARECAREnet list of cancers is available within the supplementary tables of the ‘Incidence and survival of rare cancers in the US and Europe’ research paper.

Bone cancer

Table 1: Old CdiA definition for bone cancer
Topograpy codes Histology codes
C40, C41 All except 9050–9055, 9140, 9590–9993
Table 2: RARECAREnet definition for bone cancer
Topography codes Histology codes
C40, C41 8004
C30, C32.3, C33,
C34.0, C40, C41

8800–8806, 8810–8812, 8815, 8830, 8840, 8850–8855, 8890, 8891, 8894–8896, 8900–8902, 8910, 8912,
8920, 9040–9044, 9120, 9124, 9130, 9133, 9150, 9170, 9180–9187, 9192–9195, 9220, 9221, 9230, 9231,
9240, 9242, 9243, 9250, 9260, 9364, 9473, 9540, 9560, 9561, 9571, 9580, 9581

All 9370, 9371, 9372

The new CdiA definition for bone cancer is the same as the RARECAREnet definition but also includes codes shown in Table 3.

Table 3: Additional codes to be used in the CdiA definition of bone cancer
Topography codes Histology codes
C40, C41 8000, 8002, 8003
C30, C32.3, C33, C34.0, C40, C41 9261

Soft tissue sarcoma

Table 4: Old CdiA definition for soft tissue sarcoma
Topograpy codes Histology codes
All except C40, C41 8800–8936, 8990–8992, 9040–9045, 9120–9262, 9540–9582
Table 5: RARECAREnet definition for soft tissue sarcoma
Topography codes

Histology codes

C49 8004
All except C30, C32.3, C33, C34.0, C40, C41 8710, 8711, 8714, 8800–8806, 8810–8815, 8825, 8830, 8832, 8833, 8840, 8842, 8850–8855, 8857, 8858, 8890, 8891, 8894–8896, 8900–8902, 8910, 8912, 8920, 8921, 8930, 8931, 8933–8935, 8959, 8963, 8964, 8990, 8991, 9020, 9040–9044, 9120, 9124, 9130, 9133, 9137, 9150, 9170, 9180–9183, 9185–9187, 9192–9195, 9220, 9231, 9240, 9251, 9252, 9260, 9364, 9365, 9540, 9542, 9560, 9561, 9571, 9580, 9581
All except C30, C32.3, C33, C34.0, C40, C41 and C07, C08, C44, C60, C63.2 8940
All except C30, C32.3, C33, C34.0, C40, C41 and C56, C71, C72 9473
All except C30, C32.3, C33, C34.0, C40, C41 and C71, C72 9503

The new CdiA definition for soft tissue sarcoma is the same as the RARECAREnet definition but also includes codes shown in Table 6.

Table 6: Additional codes to be used in the CdiA definition of soft tissue sarcoma
Topography codes Histology codes
All 8936, 9140
All except C30, C32.3, C33, C34.0, C40, C41 9045