ABSTRACT
BACKGROUND: During the COVID-19 pandemic, guidelines recommended that breast cancer centers delay estrogen receptor-positive breast cancer surgeries with neoadjuvant endocrine therapy. We aimed to evaluate pathologic upstaging of breast cancer patients affected by these guidelines. METHODS: Female patients with stage I/II breast cancer receiving neoadjuvant endocrine therapy were prospectively identified and were matched to a historical cohort of stage I/II estrogen receptor-positive breast cancer patients treated with upfront surgery ≤35 days. Primary outcomes were pathologic T and N upstaging versus clinical staging. RESULTS: After matching, 28 neoadjuvant endocrine therapy and 48 control patients remained. Median age in each group was 65 (P = .68). Most patients (78.6% and 79.2%) had invasive ductal carcinoma with a clinical tumor size of 0.9 cm vs 1.7 cm (P = .056). Time to surgery was 68 days in the neoadjuvant endocrine therapy group and 26.5 days in the control (P < .001). A total of 23 neoadjuvant endocrine therapy patients (82.1%) had the same or lower pT-stage compared with 31 (64.5%) control patients (P = .115). Only 3 (10.7%) neoadjuvant endocrine therapy patients had increased pN-stage vs 14 (29.2%) control patients (P = .063). CONCLUSION: Despite 2.5-times longer delays, patients with early-stage estrogen receptor-positive breast cancer receiving neoadjuvant endocrine therapy did not experience pathologic upstaging during the COVID-19 pandemic. These findings may support the use of neoadjuvant endocrine therapy in similar patients if delays to surgery are projected.