Perioperative SARS-CoV-2 infection significantly increases the risk of postoperative complications and mortality, while also exerting long-lasting impacts on multiple organs and systems. Due to the curtailment or cessation of non-emergency surgeries during the initial phase of the pandemic, there is a lack of evidence regarding the optimal timing and medium- to long-term postoperative outcomes of surgical intervention in breast cancer patients with prior SARS-CoV-2 infection, particularly after vaccination. We aim to investigate whether prior SARS-CoV-2 infection increases the risk of postoperative adverse outcomes in breast cancer patients and determine the optimal timing for surgical intervention during the pandemic, as well as to longitudinally assess the evolution of postoperative adverse outcomes within one year after COVID-19 and identify associated risk factors.

This study employs a prospective cohort design with longitudinal and matched characteristics, focusing on breast cancer patients who underwent surgery after recovering from SARS-CoV-2 infection. Patients were stratified by the time of surgery relative to COVID-19 diagnosis. The Inverse Probability of Treatment Weighting (IPTW) method was used to match a control group (COVID-19 negative) based on patient, tumor, and surgical factors in order to compare composite indicators (including death, pneumonia, thrombosis, cardiac complications, and unplanned hospitalization) for evaluating the optimal timing of surgery. We investigated the longitudinal evolution of postoperative adverse outcomes and identified the relevant risk factors through logistic regression analysis.

Inclusion Criteria:

• Breast cancer patients who underwent surgery after recovering from SARS-CoV-2 infection
• Breast cancer patients who had never been infected with SARS-CoV-2 before surgery

Exclusion Criteria:

• Distant metastasis
• Pregnancy-associated breast cancer
• Incomplete follow-up information

The first group was the resolved COVID-19 group, which served as the experimental group and included patients who had recovered from SARS-CoV-2 infection between January 2023 and March 2023 and underwent limited breast cancer operations in our Breast Surgery Department. These patients had a history of SARS-CoV-2 infection before surgery. The second group was the pre-COVID-19 group, which served as the control group and included patients who underwent limited breast cancer operations in our Breast Surgery Department between June and August 2022 and had no history of SARS-CoV-2 infection before surgery. However, these patients were diagnosed with COVID-19 after the first tumor assessment after surgery (at least 90 days after surgery) and excluded patients who had been infected with SARS-CoV-2 within 90 days after surgery or showed distant metastases.