The New Coronavirus Pandemic and the Trend of Breast Cancer Diagnosis According to Age Group: Total and Interrupted Time Series Study.

OBJECTIVE: There is a lack of studies evaluating the COVID-19 pandemic effect on breast cancer detection according to age group. This study aimed to assess the pandemic impact on the trend of mammograms, breast biopsies, and breast cancer stage at diagnosis according to age group.

METHODS: This was an ecological time series study by inflection point regression model. We used data from women aged between 30 and 49, 50 and 69, and 70 years or more available in an open-access dataset of the Brazilian public healthcare system (2017-2021). We analyzed the trend of the variables in the pre-pandemic and the pandemic effect on the total time series.

RESULTS: The decreasing or stationary trend of mammograms in the pre-pandemic has changed to a decreasing trend in the total time series in all age groups. Before the pandemic, the increasing trend of breast biopsies has changed to stationary in the total time series in all age groups. The increasing trend of tumors at stages O to II in the pre-pandemic has changed to decreasing or stationary in the total time series. Finally, the increasing trend of tumors at stage III or IV remained increasing in the total time series in all age groups.

CONCLUSION: The pandemic has changed the stationary or increasing trend to a decreasing or stationary trend of mammograms, breast biopsies, and tumors at stages 0 to II but has not influenced the increasing trend of tumors at stages III and IV in all age groups.