Outcome of T1N0M0 breast cancer in relation to St. Gallen risk assignment criteria for adjuvant therapy.

T1N0M0 (stage I) breast cancer (BC) has been increasing in recent decades but the optimal adjuvant approach remains controversial. To assess the outcome of BC patients stratified and treated with multimodal therapies according to St. Gallen consensus meeting recommendations, we retrospectively evaluated an unselected cohort of T1N0M0 BC patients, with respect to the St. Gallen criteria. At a median follow-up of 5 years, the recurrence rate, recurrence-free survival and overall survival were 7%, 94% and 96% respectively, and 60% of relapses were locoregional. No statistically significant difference was observed between T1a,b/T1c groups, or among risk categories (high/intermediate/low). The very low rate of distant recurrences even in patients with unfavorable prognostic factors seems to support the use of adjuvant systemic therapies but better prognostic and predictive factors are strongly needed for this subset of patients.