Effects of COVID-19 pandemic on breast cancer screening: A 6-year cohort study

Objective: Breast cancer screening facilitates the early detection of breast cancer and can reduce mortality among women. However, during the COVID-19 pandemic, regular screening was postponed or interrupted. This study investigated the effect of the pandemic on breast cancer screening and diagnosis rates. Methods: This single-center, retrospective cohort study enrolled women aged 40–69 years. Mammography was performed at our hospital or in outreach screening vehicles. Follow-up rate, time to follow-up, time to diagnosis, cancer detection rate (CDR), positive predictive value (PPV), and cancer staging were compared between pre-pandemic (2017–2019) and pandemic (2020–2022) periods. Results: A similar number of participants were screened during the pandemic (N = 77,901) and pre-pandemic periods (N = 75,403). However, mobile screening significantly increased from 89.4% to 94.9% during the pandemic. Education level, rate of self-examination of breasts, and the proportion of participants with a family history of breast cancer were higher during the pandemic than in the pre-pandemic period. Time to follow-up and time to diagnosis were significantly shorter during the pandemic than in the pre-pandemic period. No significant differences were observed in PPV, CDR, cancer staging, and rate of invasive carcinoma between the two periods. Conclusion: During the pandemic, participants were more likely to promptly return for follow-up. The use of outreach screening vehicles and increased awareness for individuals with low education levels are crucial for maintaining screening volumes in the pandemic recovery period. Outreach screening strategies may serve as an alternative in a future pandemic crisis.