A/Prof Paul Mitchell
An increasing proportion of patients with breast cancer are undergoing neoadjuvant treatment (NAT), that is, anti-cancer drug therapy prior to surgery. In addition, some patients, especially older women, may have drug therapy and never have surgery. Staging of early breast cancer is usually based on the findings at surgery and the surgical specimens, and is routinely reported to the Victorian Cancer Registry(VCR) by pathology services. However, where NAT is given to shrink the tumour prior to surgery, there is usually downstaging of the tumour. For patients undergoing NAT, the baseline stage at presentation is a clinical stage mostly based on radiological findings, and usually this baseline stage is much more advanced than that of the subsequent surgical specimen obtained after NAT. In the VCR these cases are recorded as unknown.
The 2021 Breast Cancer Summit identified that documentation of stage was not available to the VCR for a high proportion of cases, considered largely due to usage of neo-adjuvant therapy. This variation was prioritised:
1. There is an unacceptable number of breast patients reported with unknown stage at diagnosis.
The recommendation from the Breast Cancer Summit working party was to reduce the number of patients with invasive breast cancer and unknown stage reported in the VCR from 10% to 5% or less. Actions to enhance the reporting of breast cancer stage include undertaking a re-analysis of patients reported as un-staged with the VCR, to better understand what data are collected and how the data are reported to the VCR, in order to identify gaps and explore how staging of patients receiving NAT can be reported. The additional action to enhance the identification of NAT cases from pathology reports will increase accuracy of staging, leading to a better understanding of the burden of disease and survival patterns.
Since the Summit in 2021, a working group has been formed, including the co-chairs of the Summit, Drs Belinda Yeo and Jane Fox, ICS directors Dr Dish Herath and A/Prof Paul Mitchell, and a representative of the Victorian Cancer Registry, with the support of the Tumour Summits team.
Current actions include identification of data that are required by VCR (a data dictionary has been developed and circulated to the clinical working party), and identification of what NAT breast cancer staging data are currently collected at different sites across Victoria and how this can be collected and reported back to the VCR. In addition, existing databases / data sources including neo-adjuvant therapy cases are being examined – Epic at Peter Mac, 100 Austin /ONJCC NAT cases, and Monash Health NAT cases up to June 2021. Work on how these data can be securely transferred is ongoing.
Clinical staging data in the VCR is missed for women who have neoadjuvant treatment prior to surgery and some elderly women undergo only anti-cancer drug therapy. Cases with only pathological stage after neo-adjuvant therapy are treated as stage unknown in the registry.
It is currently thought that if clinical staging data could be collected from MDMs then these gaps may be able to be rectified.