Surgical Management of Young Women with High-Risk Breast Cancer Receiving Neoadjuvant Systemic Therapy on the I-SPY2 Trial.
BACKGROUND: Mastectomy rates in women with breast cancer are higher in younger women than in older women. The impact of this more extensive surgery on overall survival (OS) and locoregional recurrence in younger women is unknown, especially after neoadjuvant systemic therapy (NST). This study evaluated surgical management and outcomes of patients aged ≤ 45 versus > 45 years enrolled in multicenter NST clinical trial, I-SPY2.0 (NCT01042379, PMID 37325931). METHODS: We conducted a secondary data analysis comparing locoregional treatment in patients aged ≤ 45 versus > 45 years with clinical or molecular high-risk clinical stage II-III breast cancer treated from April 2010 to June 2022. Multivariate Cox proportional hazards models were used to evaluate associations between type of breast surgery with OS and locoregional recurrence-free interval by age group and tumor receptor subtype. RESULTS: Of 1737 patients, 698 (40.2%) were aged ≤ 45 years. There were no significant differences in patient or tumor characteristics or residual cancer burden distribution between age groups. Although breast-conserving surgery was significantly less common in younger women (36.8% vs 48.5%, p < 0.001), surgery type was not associated with OS or locoregional recurrence-free interval for patients aged ≤ 45 years. CONCLUSIONS: Greater extent of breast surgery was not associated with improved outcomes in women aged ≤ 45 years. Choice of surgical procedure in the management of breast cancer is multifactorial, but young age alone does not warrant mastectomy following NST.