The impact of COVID-19 on breast cancer stage at diagnosis

ABSTRACT

Background: During the SARS-CoV-2 pandemic, routine screening mammography (SM) was stopped and diagnostic mammography (DM) was limited for several months across the United States in order to reduce patient exposure and redeploy medical personnel. We hypothesized that this delay would result in patients presenting with later-stage disease following the initial shutdown. Methods: Patients diagnosed with invasive breast cancers from 2016-2020 were identified using the Beth Israel Deaconess Medical Center Cancer Registry. Baseline patient characteristics, demographics, and clinical information were gathered and cross-referenced with our electronic medical record. Late-stage disease was defined as initial anatomic stage III-IV disease in the AJCC 8th edition staging system. The control cohort consisted of patients diagnosed from 2016-2019;patients diagnosed in 2020 were the test cohort. Chi-squared analysis was used to compare monthly distributions in stage at diagnosis between the control and test cohorts. Multivariate analysis was performed using a logistic regression model. Results: There were 1597 patients diagnosed with invasive breast cancer between 2016-2019 and 333 in 2020. Median age at diagnosis was 60 years;99% were female, and 69.1% were white. Mammography was limited from 3/16/20-6/8/20, with 90% reduction in volume during this time. The number of screening studies performed in March, April, May, and June of 2020 were 987, 1, 4, and 721 compared to 2042, 2141, 2241, and 2142 in 2019. The volume of new diagnoses per month decreased substantially during the shutdown (see table). The proportion of patients diagnosed with late-stage disease was 6.6% in the control cohort compared to 12.6% in the 2020 test cohort (p < 0.001);92.9% of late-stage diagnoses in 2020 occurred from June to December following the shutdown period. On multivariate analysis, year of diagnosis (2020 vs 2016-2019;OR = 4.25 95% CI 0.035-0.095, p < 0.001), lower income (<200% of the federal poverty level;OR = 2.73 95% CI 0.016-0.099, p = 0.006) and increased Charlson Comorbidity Index (OR = 12.01 95% CI 0.037-0.052, p < 0.001) were associated with later stage at diagnosis. Conclusions: Patients were more likely to be diagnosed with late-stage breast cancer following the global shutdown due to the SARSCoV-2 pandemic. Patients with lower income and medical comorbidities were disproportionately affected. These data raise significant concerns regarding the impact of SARS-CoV-2 on cancer diagnoses and long-term outcomes, especially in vulnerable patient populations. (Table Presented).