Effect of younger age on survival outcomes in T1N0M0 breast cancer: A propensity score matching analysis

Purpose We evaluated the effect of younger age on recurrence risk in Chinese women diagnosed with T1N0M0 breast cancer (BC), using propensity score matching (PSM) analysis. Methods We included 365 women who were diagnosed with T1N0M0 BC between 2003 and 2016, and who received surgery at our center. They were classified as younger (<= 40 years) and older (>40 years). We used PSM to balance clinicopathologic characteristics between the two age groups. Survival was analyzed by the Kaplan-Meier method, before and after PSM. Results Over a median follow-up period of 79 months, 54 patients developed recurrences. Before PSM, younger patients had worse recurrence-free survival (RFS) than older patients. Significantly worse RFS was seen in younger patients with HER2(+) BC compared with their older counterparts. Younger patients had higher rates of locoregional recurrence rather than metastasis, especially in the first 5 years after diagnosis. After PSM, the two age groups still significantly differed in 5-year RFS. Conclusion Among PSM pairs with T1N0M0 BC, with equal baselines and treatment conditions, we found that patients who presented at younger ages had worse outcomes, independently of other pathological features. Younger patients with BC may require more individualized therapy to improve their prognosis.