Long-term outcomes in women diagnosed with non-invasive breast cancer (ODR1516_255)

The Data will be used for the purpose of a research project: Long-term outcomes in women diagnosed with non-invasive breast cancer (ODR1516_255)]

The Data will be used to answer the following objectives:

Primary objective:

• Characterise the risk of developing invasive breast cancer among women diagnosed with a non-invasive breast cancer, and the factors that determine this risk.

Secondary objectives:

• Characterise the risk of death from breast cancer in women diagnosed with a non-invasive breast cancer, and the factors that determine this risk.

• Characterise the risk of developing a further non-invasive breast cancer among women who have already been diagnosed with one non-invasive breast cancer, and the factors that determine this risk.

No data will flow to NHS England for the purposes of this Data Sharing Agreement (DSA).

NHS England will provide the relevant records from the datasets to University of Oxford.  The data will contain no direct identifying data items.  The Data will be pseudonymised and individuals cannot be reidentified through linkage with other data in the possession of the recipient.

The Data will not be transferred to any other location.

The Data will be stored and backed up on servers at the Clinical Trial Service Unit, Nuffield Department of Population Health at University of Oxford.

The Data will be accessed by substantive employees onsite at the premises of University of Oxford and by authorised personnel via remote access.

The Controller(s) must confirm and provide evidence upon audit by NHS England that access via any remote device complies with the data security obligations within this DSA and the Data Sharing Framework Contract.

For remote access:

• Remote access will only be from secure locations situated within the territory of use (as further restricted elsewhere within the DSA if so done) stated within this DSA;

• Access controls granting users the minimum level of access required are in place;

• Remote access is only via secure connections (e.g., VPNs or secure protocols) to protect data;

• Multifactor authentication (MFA) is required for remote access;

• Device security, including up-to-date software and operating systems, antivirus software, and enabled firewalls are utilised for the remote access;

• All remote access is undertaken within the scope of the organisation’s DSPT (or other security arrangements as per this DSA) and complies with the organisation’s remote access policy.

The above applies in addition to any condition set out elsewhere within the DSA (e.g. who may carry out processing, and for what purpose).

The Data will not be linked with any other data.

The expected outputs of the processing will be:

• Submissions to peer reviewed journals.

• Presentations at specific conferences such as the Association of Breast Surgery.

The outputs will not contain NHS England Data and will only contain aggregated information with small numbers suppressed as appropriate in line with the relevant disclosure rules for the dataset(s) from which the information was derived.

The outputs will be communicated to relevant recipients through the following dissemination channels:

• Journals

• Manuscripts

• Abstracts

• Social media

• Public reports

• Industry newsletters & press releases

The research is hoped to advance clinical understanding of DCIS, help shape national screening and treatment guidelines, improve patient care pathways, and demonstrated the value of population‑level data in informing both policy and practice. This study is expected to provide policymakers with the information needed to inform the optimal surveillance and management of DCIS. It is expected to have implications for the frequency and duration of screening mammography for women diagnosed with DCIS.

The findings of this research study are expected to contribute to evidence‑based decision‑making for policy‑makers, clinicians, and patients, informing best practice to improve the care, treatment, and experience of health care users relevant to the subject matter of the study.

The use of the data could:

• Help the system to better understand the health and care needs of populations, by documenting the long‑term outcomes of ductal carcinoma in situ (DCIS) both within and outside the NHS breast screening programme.

• Lead to the identification or improvement of treatments or interventions, by clarifying how risks of invasive breast cancer vary by tumour characteristics and treatment received, thereby influencing surgical and screening practices.

• Advance understanding of national trends in health and social care needs, particularly in relation to breast cancer incidence, mortality, and the impact of screening programmes.

• Inform planning of health services and programmes, for example by guiding decisions on the frequency and duration of mammographic screening and ensuring equitable access to effective care.

• Provide a mechanism for checking the quality of care, through evidence that has already been incorporated into NICE recommendations and the Association of Breast Surgeons’ guidance, helping to identify both areas of good practice and those requiring improvement.

• Support knowledge creation and exploratory research, by filling a major evidence gap on the natural history of DCIS and demonstrating innovative use of population‑level data to inform clinical care, policy, and future trials.

Two papers arising from this work have been published in the British Medical Journal (BMJ, Impact Factor 96). The measurable benefits to health and social care yielded to date are outlined below:

(1) Mannu GS, Wang Z, Dodwell D, Broggio J, Charman J, Darby SC. Invasive breast cancer and breast cancer death after non-screen detected ductal carcinoma in situ from 1990 to 2018 in England: population-based cohort study. BMJ. 2024; 27;369. (PMID: 38267073)

Impact: Prior to this study, the long-term outcomes following pre-invasive breast cancer, specifically ductal carcinoma in situ (DCIS), were unknown. This paper presented a population-based observational cohort study describing the long-term outcomes for all women diagnosed with DCIS outside the NHS breast screening programme in England. For the first time, the natural history of DCIS in England was documented. The findings have informed discussions on the clinical impact of the NHS screening programme and provide evidence to support the interpretation of randomised trials of breast screening. The results are expected to influence future recommendations regarding the frequency and duration of mammographic screening for women diagnosed with DCIS.

(2) Mannu GS, Wang Z, Broggio J, Charman J, Cheung S, Kearins O, Dodwell D, Darby SC. Invasive breast cancer and breast cancer mortality after ductal carcinoma in situ in women attending for breast screening in England, 1988–2014: population-based observational cohort study. BMJ. 2020 May 27;369. (PMID: 32461218)

Impact: Before this study, the optimal treatment strategy for DCIS detected through the NHS breast screening programme was unclear. This paper presented a population-based observational cohort study that provided evidence on the long-term risk of invasive disease following a diagnosis of screen-detected DCIS, and how this risk varied according to tumour characteristics and treatments received.

The findings have directly influenced the treatment of women diagnosed with DCIS in the UK and have been extensively cited in national treatment guidelines, including the National Institute for Health and Care Excellence (NICE) 2024 recommendations and the Association of Breast Surgeons’ 2024 guidance on optimal surgical margin distance. The paper’s clinical significance was further recognised through the Office for National Statistics (ONS) Research Excellence Prize 2020, and it was highlighted as the ONS Case Study of the Month for demonstrating innovative use of population-level data to inform clinical care.