Impact of the COVID-19 pandemic on breast cancer diagnosis and treatment

Abstract

Objective: To assess the impact of the COVID-19 pandemic on breast cancer diagnosis and treatment. Methods: This
is a retrospective cohort study involving patients at the Barretos Cancer Hospital diagnosed with breast cancer between
2018 and 2023. Patients were divided into three groups: pre-pandemic (2018–2019), pandemic (2020–2021), and postpandemic (2022–2023). The sample, comprising approximately 3,500 patients, was analyzed using appropriate statistical tests to evaluate associations between epidemiological, histopathological, and clinical characteristics, and cancer
outcomes. Results: Preliminary analyses revealed significant variations in diagnosis and treatment during the three
periods. There was an increase in the age of patients post-pandemic, with more women over 60 years (24.9%; p<0.0001).
Clinical staging showed a decrease in stage I (from 23.4% to 14.9%) and an increase in stage III (from 29.6% to 36.7%) during the pandemic, indicating more advanced diagnoses (p=0.0082). Pathological staging followed a similar trend, with
a decrease in stage I and an increase in stage II (38.1% post-pandemic). Initial treatment also changed, with a reduction
in surgeries during the pandemic (from 59.3% to 37.7%) and an increase in exclusive palliative care (from 0.4% to 2.4%).
The use of neoadjuvant hormone therapy was notable during the pandemic (18.1%). The type of surgery varied, with an
increase in quadrantectomy in the post-pandemic (from 54.4% to 67.2%) and a decrease in mastectomy with immediate
reconstruction (from 23.5% to 17.0%). There was a significant increase in the luminal B HER-negative molecular subtype
post-pandemic (from 8.2% to 35.3%; p<0.0001). Conclusion: The COVID-19 pandemic significantly impacted the diagnosis and treatment of breast cancer, leading to later diagnosis and changes in treatment modalities.