Timing of surgery and 1‐year postoperative outcomes in patients with breast cancer and preoperative <scp>COVID</scp>‐19 history: A matched, longitudinal, ambidirectional cohort study

Preoperative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection increases the risk of postoperative complications and mortality and has long-lasting effects on multiple organ systems. The scheduling of elective surgery after SARS-CoV-2 infection depends on infection severity, vaccination status, patient factors, and surgical urgency. In the post-vaccination Omicron era of the coronavirus disease 2019 (COVID-19) pandemic, there is limited evidence regarding the medium- and long-term postoperative outcomes and optimal surgical timing for patients with breast cancer recovering from COVID-19. This ambidirectional cohort study included 392 patients who underwent breast cancer surgery either more than 2 weeks after or 12 weeks before a COVID-19 diagnosis. Patients were stratified according to the time from COVID-19 diagnosis to surgery and were followed longitudinally for 1 year to evaluate the evolution of postoperative outcomes. Propensity score matching and stabilized inverse probability of treatment weighting methods were used to mitigate confounding factors, determine the optimal timing of surgery, and assess risk factors. No deaths or severe postoperative complications occurred within 1 year of surgery. Patients with preoperative COVID-19 history had a higher risk of medium-term adverse postoperative outcomes than those without (26.2% vs. 10.2%). Multiple analyses revealed that for patients with breast cancer and preoperative COVID-19 history, delaying surgery beyond 4 or even 8 weeks after COVID-19 diagnosis did not significantly reduce the risk of medium- or long-term adverse postoperative outcomes (p > .05). In the post-vaccination Omicron era, our evidence supports timely performing surgery 2 weeks after COVID-19 diagnosis in fully vaccinated patients with breast cancer.