Impact of COVID-19 on the clinical staging of breast cancer: A cross-sectional study

Following the declaration of COVID-19 as a pandemic in February 2020, one of the most important public health impacts was the decrease in demand for screening mammography, with a consequent impact on the early diagnosis of breast cancer. Therefore, the aim of this study was to compare the initial clinical staging of women with breast cancer in the pre-pandemic and pandemic periods at a reference cancer hospital in southern Brazil. We performed a retrospective cross-sectional study with a database of surgical procedures on the female breast, comparing the years 2019 and 2020. A total of 1733 surgical procedures for diagnostic and curative purposes were evaluated. Among these patients, 491 (49.2 %) were diagnosed with breast cancer in 2019 and 335 (45.5 %) in 2020. We excluded 907 patients due to benign diagnoses, carcinoma in situ, recurrence, presence of metastases, missing data, and other findings. When comparing 2019 and 2020, we found no significant difference in clinical staging or tumor phenotype. The median time in days between mammography and first treatment was also similar in both years. However, we observed a higher frequency of lobular histologies and neoadjuvant therapy as first treatment choice in the pandemic year. In conclusion, there was no significant difference in clinical staging between women diagnosed with breast cancer before and during the pandemic.