COVID-19 and Breast Cancer: Analysis of Surgical Management of a Large Referral Center during the 2020-2021 Pandemic Period

Background: Coronavirus disease-19 (COVID-19) has spread worldwide since December 2019 and was officially declared a pandemic in March 2020. Due to the rapid transmission and the high fatality rate, drastic emergency restrictions were issued, with a negative impact on routine clinical activities. In particular, in Italy, many authors have reported a reduction in the number of breast cancer diagnoses and critical problems in the management of patients who accessed the breast units during the dramatic first months of the pandemic. Our study aims to analyze the global impact of COVID-19 in the two years of the pandemic (2020-2021) on the surgical management of breast cancer by comparing them with the previous two years. Methods: In our retrospective study, we analyzed all cases of breast cancer diagnosed and surgically treated at the breast unit of "Città della Salute e della Scienza" in Turin, Italy, making a comparison between the 2018-2019 pre-pandemic period and the 2020-2021 pandemic period. Results: We included in our analysis 1331 breast cancer cases surgically treated from January 2018 to December 2021. A total of 726 patients were treated in the pre-pandemic years and 605 in the pandemic period (-121 cases, 9%). No significant differences were observed regarding diagnosis (screening vs. no screening) and timing between radiological diagnosis and surgery for both in situ and invasive tumors. There were no variations in the breast surgical approach (mastectomy vs. conservative surgery), while a reduction in axillary dissection compared to the sentinel lymph node in the pandemic period was observed (p-value < 0.001). Regarding the biological characteristics of breast cancers, we observed a greater number of grades 2-3 (p-value = 0.007), pT stage 3-4 breast cancer surgically treated without previous neoadjuvant chemotherapy (p-value = 0.03), and a reduction in luminal B tumors (p-value = 0.007). Conclusions: Overall, we report a limited reduction in surgical activity for breast cancer treatment considering the entire pandemic period (2020-2021). These results suggest a prompt resumption of surgical activity similar to the pre-pandemic period.