Abstract
BACKGROUND: We aim to determine clinical and pathological stage discordance rates and to evaluate factors associated with discordance. METHODS: Adults with clinical stages I-III breast cancer were identified from the National Cancer Data Base. Concordance was defined as cTN = pTN (discordance: cTN≠pTN). Multivariate logistic regression was used to identify factors associated with discordance. RESULTS: Comparing clinical and pathological stage, 23.1% were downstaged and 8.7% were upstaged. After adjustment, factors associated with downstaging (vs concordance) included grade 3 (OR 10.56, vs grade 1) and HER2-negative (OR 3.79). Factors associated with upstaging (vs concordance) were grade 3 (OR 10.56, vs grade 1), HER2-negative (OR 1.25), and lobular histology (OR 2.47, vs ductal). ER-negative status was associated with stage concordance (vs downstaged or upstaged, OR 0.52 and 0.87). CONCLUSIONS: Among breast cancer patients, nearly one-third exhibit clinical-pathological stage discordance. This high likelihood of discordance is important to consider for counseling and treatment planning.