Background: The COVID-19 pandemic rapidly altered health care worldwide. To save protective equipment and minimize exposures, many hospitals stopped some or all cancer surgery, leading oncologic providers to quickly adjust patient management. The goal of this study is to describe the breast cancer patient level changes which occurred during the initial months of COVID-19 in the United States. Methods: The American Society of Breast Surgeons developed a COVID-19 specific registry, within the established HIPPA compliant Mastery of Breast Surgery Program. Surgeons entered patient demographic data as well as their surgical and medical care (Neoadjuvant endocrine (NET) vs Neoadjuvant chemotherapy (NCT)). Data fields tracked whether decisions were usual for that practice, or modified due to COVID-19. Results: Between 3/1 and 6/17/2020, data from 1781 patients was entered by 154 surgeons. Mean age was 63, 78% Caucasian, 10% African American, 6% Hispanic; with geographic distribution ranging from 10.8% Northwest to 29.5% Northeast. Initial consultation took place in-person for 94.8% and only 5.2% (89) occurred via video/telephone. To date, just over 1% (14) of patients tested positive for COVID-19. Mean invasive tumor size was 21.2mm and 15.7% were node positive. Of 1445 invasive breast cancers 75% (1081) were ER +/HER2-, 13.5% (195) HER2+, 11.1% (160) triple negative (TNBC) (9/missing data). DCIS comprised 18.2% (325) of the cohort. Of 267 cases of ER+ DCIS, 49% (131) had primary surgery and 49% (130) received NET. The majority of NET use was due to COVID-19, 95% (124). Almost all (50/52) ER- DCIS underwent primary surgery (6/missing ER). Table 1 describes the management for the 1436 patients with invasive cancer with known biomarkers. NET due to COVID-19 was utilized in 45% (482), with only 5% (54) as part of usual practice. Increasing age was not a statistically significant factor in the use of NET (OR 0.99, 95% CI 0.97-1.01). In comparison to patients from the Northwest, patients from the Southwest and Northeast had the greatest use of NET(COVID-19) vs NET(usual) (ORs 14.4 and 4.6) Genomic assay testing was performed on the core biopsy in 216 patients, with 65% (141) due to COVID-19. Among the patients who had genomic testing due to COVID-19, 116 (82%) had NET, 18 (13%) had NCT, with the remaining having primary surgery. Of 472 patients treated with primary surgery for which the impact of COVID-19 was provided, surgery was delayed in 20% (96). Patients from the Northeast had a 2.1 x greater odds of having surgery delayed in comparison to those from the Midwest. Patients also experienced changes to their surgical plan with the most common changes being 6% (27) converting from mastectomy to breast conservation and 7% (34) from mastectomy with reconstruction to mastectomy without reconstruction. Conclusion: COVID-19 led to significant modifications in breast cancer treatment, including high rates of NET, genomic assay testing on core biopsies as well as delays in surgery; each of which were consistent with the prioritization and treatment recommendations from the COVID-19 Pandemic Breast Cancer Consortium. The majority of patients with TNBC and HER2+ disease received guideline concordant NCT. The ASBrS Mastery COVID-19 registry provides a snapshot into the rapid care changes caused by the pandemic, has ongoing data entry and analysis and will enable understanding of the impact on long term breast cancer outcomes.

Table 1: Biomarker specific treatments

ER+/HER2- (1081)TNBC (160)HER2+/any ER (195)
Mean Age 65 61 59 
African American (%) 97(9%) 21(13%) 27(14%) 
Primary Surgery (usual) 386 (36%) 50 (31%) 37 (19%) 
Primary Surgery (COVID-19) 28 (2.6%) 6 (3.7%) 6 (3.1%) 
NET (usual) 54 (5%) NA 1(0.5%) 
NET (COVID-19) 482 (45%) NA 6 (3.6%) 
NCT (usual) 90 (8.3%) 98 (61%) 137 (70%) 
NCT (COVID-19) 39 (3.6%) 6 (3.7%) 8 (4.1%) 
ER+/HER2- (1081)TNBC (160)HER2+/any ER (195)
Mean Age 65 61 59 
African American (%) 97(9%) 21(13%) 27(14%) 
Primary Surgery (usual) 386 (36%) 50 (31%) 37 (19%) 
Primary Surgery (COVID-19) 28 (2.6%) 6 (3.7%) 6 (3.1%) 
NET (usual) 54 (5%) NA 1(0.5%) 
NET (COVID-19) 482 (45%) NA 6 (3.6%) 
NCT (usual) 90 (8.3%) 98 (61%) 137 (70%) 
NCT (COVID-19) 39 (3.6%) 6 (3.7%) 8 (4.1%) 

Citation Format: Lee Gravatt Wilke, Toan T Nguyen, Qiuyu Yang, Bret M Hanlon, Kathryn A Wagner, Pamela Strickland, Eric A Brown, Jill Dietz, Judy C Boughey. Impact of the COVID-19 pandemic on the multidisciplinary management of breast cancer: Initial analysis of the american society of breast surgeons mastery COVID-19 registry [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SS2-01.