Evaluation of factors related to efficacy and safety of neo/adjuvant chemotherapy for breast cancer as a brief estimate of the impact of COVID-19 pandemic

Background COVID-19 pandemic presented as a challenge to breast cancer (BC) treatment, especially considering safety concerns and resource scarcity Treatment choices have been taken mainly based on safety according to guidelines which aim hierarchically categorize the clinical benefits of any clinical decision Considering the magnitude of benefit, neo/adjuvant breast cancer treatment is positioned at medium/high levels Despite these recommendations, patients might be refusing chemotherapy (CT) or avoiding emergency care utilization due to concerns about COVID- 19 infection There have been described factors related to the reduction of effectiveness of neo/adjuvant CT for breast cancer, like relative intensity dose (RDI) 85% before the pandemic, similar to the literature Despite the lower rate of RDI <85% during pandemic (6%), this may be related to treatments that are still in progress, greater refusal of chemotherapy by patients with morbidities or advanced age, or even related to treatment modification aiming to minimize toxicities and avoid interruptions (ie prescription of colony-stimulating factors) Further analysis may help to identify the factors related to these findings Despite this, every effort must be made to achieve the maximum effectiveness of CT and to ensure safety during treatment The impact of treatment modifications should be monitored to minimize unfavorable outcomes