D131. Breast Cancer Surgery and Stage Change during the COVID-19 Pandemic: An Observational Cohort

PURPOSE: The COVID-19 pandemic restricted non-emergent surgery and increased time-to-surgery (TSS). Resultant changes in medical and surgical breast cancer treatment during this time warrant further characterization to optimize care. Our study aims to assess the implications of the COVID-19 pandemic on the progression of (tumor, nodal, metastasis) TNM stage in patients surgically treated for primary breast cancer. METHODS: This multicenter observational study includes 1,215 patients receiving oncologic breast surgery before (January 2018-December 2019; ‘pre-COVID’) and during (January 2020-July 2022; ‘COVID’) the outbreak of the COVID-19 pandemic. Data related to patient characteristics, cancer, treatment, and disease progression were evaluated. RESULTS: Preliminary analysis included 108 patients and revealed no significant differences in covariates between groups. TTS was similar in pre-COVID (37; 66 days) and COVID cohorts (71; 69 days). However, the incidence of anatomic upstaging was higher in the pre-COVID cohort (10, 27.0%) than in the COVID cohort (12, 17.1%), with reciprocal trends in downstaging (pre-COVID: 4, 10.3%; COVID: 10, 14.3%), although this did not reach significance. While the use of neoadjuvant therapy was rare pre-COVID (neoadjuvant chemotherapy: 1, 2.7%; hormone therapy: 2, 5.4%), usage increased during COVID (neoadjuvant chemotherapy: 4, 6.0%; hormone therapy: 9, 13.4%; p>0.05). CONCLUSION: This preliminary analysis suggests that the increased use of neoadjuvant therapy during the COVID-19 pandemic may have prevented upstaging. Further characterization of this large registry will add to the reported literature on evidence-based strategies for breast cancer treatment.