ABSTRACT
BACKGROUND: Cancer patients had been profoundly affected by the outbreak of COVID-19 especially after quarantine restrictions in China. We aimed to explore the treatment changes and delays of early breast cancer (EBC) during the first quarter of 2020. METHODS: We did this retrospective, multicentre, cohort study at 97 cancer centres in China. EBC patients who received treatment regardless of preoperative therapy, surgery or postoperative therapy during first quarter of 2020 were included. FINDINGS: 8397 patients were eligible with a median age of 50 (IQR 43-56). 0·2% (15/8397) of EBC patients were confirmed as COVID-19 infection. Only 5·2% of breast cancer diagnosis occurred after quarantine in Hubei compared with 15·3% in other provinces (OR= 0·30, 95%CI 0·24-0·38). postoperative endocrine therapy were least affected compared with different regions after quarantine (OR=0·37 [95%CI 0·19-0·73]). The proportion of surgery decreased from 16·4% in December last year to 2·6% in February in Hubei. Compared with intervals from diagnosis to treatment before quarantine restrictions, the average time increased with significance from 3·5 to 7·7 days in Hubei and 5·7 to 7·7 days in other provinces (p< 0·001). There were also 18·5 and 7·2 days delay in Hubei and other provinces respectively when calculating interval from surgery to postoperative therapy. INTERPRETATION: EBC from high risk regions had a comparative rate of COVID-19 infection. After implementation of COVID-19 quarantine restrictions, fewer diagnosis and surgery with significant delays were seen when compared with treatment before. FUNDING: Beijing Medical Award Foundation (YJ0120).