Impact of COVID-19 pandemic in 2020 on the diagnosis and management of breast cancer in Korea: A multi-institutional study.
Authors: Kang Young-Joon , Oh Se Jeong , Baek Jong Min , Kim Yong-seok , Jeon Ye Won , Yoo Tae-Kyung , Rhu Jiyoung , Shin Chang-Hyun , Cho Shijin , Choi Hoon 
Published: June 2021

10566 Background: Since the COVID-19 pandemic began in early 2020, there have been many reports that it has had a significant impact on screening, case identification and referral in cancer diagnosis. We investigated the diagnostic and therapeutic status of breast malignancy before and after the COVID-19 pandemic at the multi-institution level. Methods: We have reviewed the records of patients with breast cancer from February 2019 to July 2020 in six university hospitals in Korea. The patients were divided into two groups according to the initial date of cancer diagnosis: Period A, from February to April and Period B, from May to July in 2020. The two groups were compared for the same periods in 2019. The goals were to determine whether breast cancer screening and diagnosis have been delayed and thus resulted in stage migration. We also examined the difference in the number of surgeries in patients diagnosed with breast cancer during those periods. Results: The total of 1,669 breast malignancy diagnosis was made in the grouped periods of 2019, and 1,369 diagnoses in 2020. All patients were screened by PCR test for COVID-19 prior to hospitalization, and none of them tested positive. Overall, there was a 9.9% reduction in the number of diagnoses than in 2019 and the decrease was more significant in Period A (11.1% vs. 8.7%). According to the age, there was no difference until the 30s but decreased from those in their 40s and above. The decline was more pronounced in the elderly. The COVID-19 pandemic has affected breast cancer screening (decreased by 27.4%) and more diminished in Period A (41.0% vs. 19.0%). Invasive breast cancer stage was not statistically different in Period A compare with 2019 (p = 0.170). But the stage in Period B was different (p = 0.032), and more patients were observed in advanced stages in 2020. The decrease in surgery was noticeably observed in Period A (4.6%, from 480 to 438 surgeries) and not in Period B. The analysis of reconstruction surgery was similar. Conclusions: Patients with COVID-19 increased exponentially from late February in Korea. However, the number of patients per day decreased to less than 100 on March 15 and then flattened. The health care system for cancer was not overloaded and restrictions on visiting hospital were minimal. Analysis in the pandemic period of the 6-month showed that the number of breast cancer screening, diagnosis and surgeries decreased compared with the previous year. Those decreases were prominent in Period A when the COVID-19 patient surged. The upstage migration of breast cancer was generally insignificant but slightly occurred in Period B. The outbreak of infectious disease makes patients reluctant to come to the hospital, especially in the elderly. We need to discuss the potential long-lasting deleterious effect of the COVID-19 pandemic on cancer diagnosis and management. And we should prepare for how to deal with the backlog caused by the COVID-19 pandemic.