Has the COVID-19 pandemic resulted in more advanced breast cancer? A hospital-based retrospective study

Background: The suspension of breast cancer screening during the COVID-19 pandemic altered patient diagnosis and management. This study investigates the impact of the COVID-19 lockdowns, screening delays and reduced healthcare attendance on changes in tumour and treatment characteristics, particularly for biologically more aggressive breast cancers. Methods: This retrospective single-hospital analysis utilized data from a prospective cancer database between July 2019 and June 2022. Patient, tumour and treatment factors were compared across pre-pandemic, pandemic and post-pandemic groups. Results: Symptomatic breast cancer increased from 42.3% in the pre-, 53.1% in the pandemic and 57% in the post- respectively (P ≤ 0.05). Compared to the pre-pandemic group (4.6%), an increase in stages 3 or 4 breast cancers in the pandemic (8.5%) and post-pandemic (7.1%) was found. Increased node-positivity in Ki67 > 20%, grade 3 or ER- tumours post-pandemic (+5.4%, +14.8%, +33.4%, respectively) was identified. More neoadjuvant chemotherapy was found in both the pandemic (+4.3%) and post-pandemic (+11.3%, P = 0.0261) groups. An increase in hypofractionated radiotherapy in the post-pandemic group (+9.4%) was also identified. Conclusion: Our study identified a decrease in early-stage cancers and an increase in node positivity, particularly for biologically more aggressive tumours. An increase in the number of patients receiving neoadjuvant chemotherapy or hypofractionated radiotherapy during the pandemic and post-pandemic periods was also identified.