Study protocol: Impact of COVID-19 on Breast Cancer Patients and Services in a UK region: protocol for a mixed methods study.

Background<br/>Globally, breast cancer screening, diagnosis and treatment services were significantly<br/>impacted by the COVID-19 pandemic. Locally, the Northern Ireland Cancer Registry<br/>(NICR) reported an 11% reduction in breast cancers diagnosed April-December 2020<br/>compared with the same period 2018−2019 despite an expected increase. This study<br/>aims to identify how the patient journey was impacted by the COVID-19 pandemic<br/>and how service provision can be improved.<br/>Methods<br/>Population-based quantitative data will be collected by NICR for individuals diagnosed with invasive breast cancer (ICD 10 code C50). Data on presentation, investigations, comorbidities (including COVID-19 infection), molecular markers, stage at<br/>diagnosis, treatment, and survival will be examined. Two time periods will be compared: March-December 2018 (pre-COVID-19 cohort) and March-December 2020<br/>(COVID-19 cohort). Analysis will include descriptive statistics, chi-square tests and<br/>ANOVAs. Patient experiences of living with breast cancer and interacting with the<br/>healthcare system during the pandemic (March 2020-April 2024) will be captured<br/>through an online, self-completed, anonymous cross-sectional international survey.<br/>Quality of life will be captured in the survey using the EQ-5D-3L. Detailed descriptive<br/>qualitative interviews will be undertaken to better understand the lived experience<br/>of breast cancer and recommend ways that services and support programs can<br/>PLOS One | https://doi.org/10.1371/journal.pone.0333288 September 29, 2025 2 / 9<br/>effectively meet the needs of this patient group. This study benefits from the inclusion<br/>of patient representatives who have been involved since the inception of this project.<br/>Discussion<br/>This study aims to quantify the impact of the COVID-19 pandemic on breast cancer<br/>patient outcomes in a UK region and make recommendations to improve patient care<br/>and outcomes in the short and long term.