University of Wisconsin–Madison Medical College of Wisconsin

Matched Case Control Analysis of Breast Cancer- Specific Factors Affecting Risk of Developing SARS-CoV-2 Infection

Michael Pierro, MD; Joanna Zurko, MD; Aniko Szabo, PhD; Yee Chung Cheng, MD; Sailaja Kamaraju, MD; John Burfeind, MD; Janet Retseck, MD PhD; Christopher R. Chitambar, MD; Lubna N. Chaudhary, MD

WMJ. 2023;122(5):418-421

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Introduction: In this retrospective matched case control study, we aim to identify breast cancer-related risk factors associated with developing COVID-19 and describe outcomes of patients with breast cancer diagnosed with COVID-19.

Methods: Women with breast cancer treated at the Medical College of Wisconsin and diagnosed with COVID-19 from March through December 2020 served as cases, and those without COVID-19 within the same timeframe served as controls. Univariate and multivariate comparisons were performed.

Results: Twenty-five cases and 77 controls were identified. All cases were fully matched by age, obesity, county, and race. Mean age was 54.6 versus 54.9, body mass index 31.0 versus 31.6, 48% lived in Milwaukee County, and 68% were White. Regarding COVID-19 outcomes, 24.0% (n = 6) of cases were hospitalized, median length of stay was 2 days, 8% (n=2) needed oxygen, 4% (n = 6) were intubated, and 4% (n = 6) died. COVID-19 led to treatment delays in 40% of cases. On univariate analysis, there was no statistically significant difference in hormone receptor status or breast cancer stage. Being on active chemotherapy (OR 5.8, P = 0.043) significantly increased the likelihood of developing COVID-19.

Conclusions: In this matched case control study of patients with breast cancer, active chemotherapy was significantly associated with an increased likelihood of developing COVID-19, with a trend seen for triple negative disease. These findings support continued strict precautions for those on active chemotherapy and warrant further analysis in those with triple negative disease.

Author Affiliations: Division of Hematology and Oncology, Department of Medicine, Medical College of Wisconsin (MCW), Milwaukee, Wisconsin (Pierro, Zurko, Cheng, Kamaraju, Burfeind, Retseck, Chitambar, Chaudhary); Division of Biostatistics, MCW, Milwaukee, Wis (Szabo).
Corresponding Author: Michael Pierro, MD, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226l; phone 414.805.3000; email; ORCID ID 0000-0003-1047-7614
Funding/Support: This project was supported by the National Center for Advancing Translational Sciences, National Institutes of Health (NIH), Award Number KL2TR001438. The content is solely the responsibility of the author(s) and does not necessarily represent the official views of the NIH.
Financial Disclosures: Dr Chaudhary reports receiving consulting fees for serving on the advisory boards of Seattle Genetics, AstraZeneca, Novartis Oncology, and Puma Biotechnology.
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