Direct and indirect effects of COVID-19 on short-term mortality of breast cancer patients.

Abstract

We studied the COVID-19 impact in newly-diagnosed breast cancer (7,349 patients in 2019, and 5,563 in 2020). In 2020 there were two diagnostic drops: -37.2% (March-May), -15.8% (October-December). Early-stage at presentation (76.4% vs. 74.4%, p=0.0013), conserving surgery (71.0% vs. 67.0%, p<0.0001), chemotherapy (86.2% vs. 53.4%, p<0.0001), and radiotherapy (65.7% vs. 42.1%, p<0.0001) decreased in 2020 compared to 2019. COVID-19 occurred in 250 patients (4.49%). The time-dependent COVID-19 effect was associated with mortality (multivariable Cox analysis HR [95% CI] 2.26 [1.35-3.74]; p=0.0018). Survival within the year of diagnosis was 97.6% in 2020 and 98.3% in 2019; 30-day mortality was 1.13% in 2020 (1.07 in uninfected patients), and 0.61% in 2019. The year of diagnosis lost its prognostic relevance after adjusting for stage and treatment. These findings emphasize the critical role of continuity of care, which was disrupted during the pandemic, and underscore the need for policies minimizing treatment initiation delay in newly diagnosed breast cancer patients.