Background: The Coronavirus Disease 2019 (COVID-19) pandemic has changed the delivery of cancer care and may have impacted the treatment outcomes. This study described the preliminary outcomes in non-metastatic breast cancer (BC) patients before and during the COVID-19 pandemic. Methods: This retrospective study included adult patients newly diagnosed with non-metastatic BC at two community cancer centers in southeast Texas. Patients diagnosed from 1/2018-10/2018 were included in the control group. Patients diagnosed from 4/2020-1/2021 were included in the COVID-19 group. The key outcomes were progression free survival (PFS), overall survival (OS), breast conserving surgery (BCS) rate, pathological complete response (PCR) rate, and time to treatment initiation (TTI). Results: The study included 74 patients (Table). The proportion of patients with self-detected BC was numerically higher in the COVID-19 group (55%) compared to the control group (36%), although this was not statistically significant (P = 0.09). The median follow-up periods were 38 (IQR: 36-43) months in the control group and 15 (IQR: 13-17) months in the COVID-19 group. No significant difference was observed in PFS (P = 0.74), with 1-year PFS of 93% (95%CI: 80%-98%) in the control group and 100% in the COVID-19 group. No significant difference was observed in OS (p = 0.22), with 1-year OS of 98% (95%CI 85%-100%) in the control group and 100% in the COVID-19 group. No significant difference was observed in TTI between control (51 days) and COVID-19 groups (52 days) (95%CI: -14 to 13; P = 0.91). Among patients who received neoadjuvant systemic therapy and surgery, BCS rates were 29% (5/17) in the control group and 50% (5/10) in the COVID-19 group (P = 0.42). Among patients who had triple negative or HER2 positive BC and received neoadjuvant systemic therapy and surgery, PCR rates were 57% (4/7) in the control group and 33% (1/3) in the COVID-19 group. Conclusions: Although total patient volume decreased during the COVID-19 pandemic, no significant difference was observed in clinical outcomes when comparing patients diagnosed with non-metastatic BC during and prior to the pandemic. Ongoing monitoring with a larger study population and longer follow-up period will help to elucidate the long-term impact of COVID-19 on BC treatment.