The impact of the COVID-19 pandemic on symptomatic breast cancer presentations in an Irish breast cancer unit: a retrospective cohort study

Background: The coronavirus-19 (COVID-19) pandemic caused delays in the diagnosis and management of breast cancer which may have affected disease presentation. The aim of this study was to compare rates of metastatic disease, tumour characteristics and management in breast cancer patients diagnosed before and after the onset of COVID-19.

Methods: A retrospective chart review was conducted on patients in a university teaching hospital who were diagnosed with invasive symptomatic breast cancer in 2019 (prepandemic control group) and in 2020, 2021, and 2022 (pandemic study groups). Rates of new metastatic presentations, tumour histopathological characteristics, operation type, and therapies administered were statistically compared.

Results: A total of 1416 patients were identified. There was a significant increase in new metastatic breast cancer presentations in 2022 compared to 2019 (14.0% vs 3.8%, p ≤ 0.001), with non-significant increases in 2020 and 2021. Rates of adjuvant radiotherapy increased in 2020 and decreased in 2022 compared to 2019, with no significant change in neoadjuvant or adjuvant chemotherapy rates. Rates of axillary surgery increased during 2020 and 2021. There was an increase in high-grade tumours and lymphovascular invasion (LVI), and less frequent oestrogen receptor (ER) positivity in pandemic groups. No significant change was noted in BCS to mastectomy ratios, overall nodal positivity rates, or median tumour size.

Conclusion: Symptomatic breast cancers diagnosed since the onset of COVID-19 demonstrated an increase in new metastatic presentations and more aggressive histopathological characteristics when compared to a pre-pandemic control group. Rates of adjuvant radiotherapy and axillary surgery increased during the pandemic.