Recently the British Journal of Cancer published a study on the short-term breast cancer survival in England in relation to ethnicity and key tumour characteristics.
It shows that the excess mortality among black women with breast cancer is attributable to socio-economic, tumour stage and biological factors.
The project was undertaken as part of a partnership between PHE and academia: work involved colleagues from PHE and researchers in King’s College London, Aarhus University in Denmark, University of Leeds and London School of Hygiene and Tropical Medicine.
Population level cancer data
Population-level data are potentially very powerful: it allows researchers and clinicians to understand the reality of treatment outcomes and survival in general clinical practice; and it also provides enough statistical power to identify significant variations which may be undetectable in smaller studies.
The combination of population-level data with a high granularity of clinical information provides a valuable opportunity to ask questions which require clinical detail on a large-scale.
The National Cancer Registration and Analysis Service (NCRAS) registers all cancers diagnosed in England. A number of data sources are used for this, including the Cancer Outcomes and Services Dataset (the national standard for reporting cancer in the NHS in England), the Systemic Anti-Cancer Therapy dataset and the Radiotherapy Dataset.
In recent years a high priority has been given to improving the recording of cancer stage and other prognostic clinical data items and this allows us to understand the variation in care while at the same time has opening opportunities for new research questions to be answered.
New insights
Previous research has shown that black women have poorer survival from breast cancer than white women. The incomplete recording of important prognostic factors has prevented large-scale, national analysis of cancer survival and prognostic factors by ethnicity in England.
This study used the improved recording of clinical data items to try and further understand the reason for this discrepancy. The difference in excess mortality was analysed by socio-economic factors, tumour stage and tumour biology.
The study published in the BJC today used information on 86,852 women diagnosed with breast cancer in England during 2012 to 2013.
The women were followed up to the end of December 2014 for their outcome. There were 8,761 deaths amongst these women, and breast cancer was the underlying cause for 70% of the women with an available cause of death recorded.
The main finding from this study was that the excess mortality of black women with breast cancer has contributions from all of the factors listed above.
It was attributable in sequence to socio-economic status and comorbidity (together around 32%), then to tumour stage (22%) and then to biological characteristics (grade, morphology, and receptors) (14%), leaving around 31% unexplained.
The unexplained proportion may be due to factors which are not recorded, or due to variation in treatment which was not analysed here.
The excess mortality of black women was much stronger in young women (0-49 years) than in middle-aged and older women (50+ years), and the effect in the younger group did not change substantially when adjustments were made for the above factors.
The group of women where the difference between black and white women was largest is young breast cancer patients in London who had stage 4 (late stage) cancers.
These findings have identified a subpopulation at most risk. Analyses such as this can contribute to risk stratification when developing future clinical guidelines and are the first step to using this data to inform the direct care of individuals.
Power of academic partnerships
Peer-review publications are an important output for all scientific work as they provide a robust and tested process to ensure the quality of the methods and validity of the conclusions.
Public Health England recognises that collaborations with academia are a vital part of this. NCRAS is in a unique position as the wealth of high-quality information collected on all the cancer patients in England means there are numerous research questions that can now be pursued.
Partnerships allow researchers to work alongside NCRAS analysts who have deep knowledge of the data within the strict information governance arrangement that protects patient confidentiality within the secure environment of PHE.
As well as bringing together experienced teams from different backgrounds and organisations it also enables PHE to undertake research which we would not otherwise have the capacity or resource to do. New insights into patient outcomes such as those published today are testament to the benefit that partnership working can provide.
About the National Cancer Registration and Analysis Service
Public Health England manages the National Disease Registers for England and this includes the National Cancer Registration and Analysis Service.
NCRAS collects detailed data on every patient with cancer into the secure environment within PHE – it can only be used to support healthcare purposes and is never sold.
More information about the Service can be found in this patient leaflet – including what data we collect, how it is used and how you can opt out should you wish.