Residual risk of breast cancer recurrence 5 years after adjuvant therapy.

There is limited prognostic information to identify breast cancer patients who are at risk for late recurrences after adjuvant or neoadjuvant systemic therapy (AST). We evaluated the residual risk of recurrence and prognostic factors of 2838 patients with stage I-III breast cancer who were treated with AST between January 1, 1985, and November 1, 2001, and remained disease free for 5 years. Residual recurrence-free survival was estimated from the landmark of 5 years after AST to date of first recurrence or last follow-up using the Kaplan-Meier method. The log-rank test (two-sided) was used to compare groups. Residual recurrence-free survival rates at 5 and 10 years were 89% and 80%, respectively, and 216 patients developed a recurrence event. The 5-year residual risks of recurrence for patients with stage I, II, and III cancers were 7% (95% confidence interval [CI] = 3% to 15%), 11% (95% CI = 9% to 13%), and 13% (95% CI = 10% to 17%), respectively (P = .02). In multivariable analysis, stage, grade, hormone receptor status, and endocrine therapy were associated with late recurrences. Breast cancer patients have a substantial residual risk of recurrence, and selected tumor characteristics are associated with late recurrences.