2802 - Disease-Free Interval as an Independent Predictor of Survival Following Ipsilateral Recurrence of Early-Stage Breast Cancer
Presenter(s)
D. G. Miller1, L. A. Boe2, B. A. Mueller1, D. A. Roth O’Brien1, G. E. Naoum1, Z. Abou Yehia1, Q. LaPlant1, J. J. Cuaron1, A. J. Khan1, S. N. Powell1, I. J. Choi1, and L. Z. Braunstein1; 1Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, 2Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY
Purpose/Objective(s): While contemporary outcomes for early-stage breast cancer are excellent, patients with isolated ipsilateral breast recurrence (IBR) face heterogenous clinical trajectories. Identifying risk factors following IBR can improve salvage treatment selection. Disease-free interval (DFI; the time from initial breast cancer diagnosis to recurrence) may be prognostic of subsequent outcomes, but evidence is limited. We evaluated whether DFI is independently associated with overall survival (OS) and distant metastasis-free survival (DMFS) in a large, contemporary cohort of patients with early-stage breast cancer who had IBR.
Materials/Methods: Using a prospectively maintained institutional database, we studied patients with T1N0-1 or T2N0 invasive breast cancer who were treated curatively and subsequently had an isolated IBR. The primary exposure was DFI, and primary endpoints included OS and DMFS from the date of IBR. Outcomes were compared across DFI categories (<2, 2-5, 5-10, and =10 years) using Kaplan-Meier analysis and log-rank tests. Multivariable Cox models evaluated continuous DFI as an independent predictor of OS and DMFS, adjusting for clinicopathologic and treatment characteristics of the initial diagnosis.
Results: We identified 818 patients with IBR at a median DFI of 4 years. Median follow-up following IBR was 42 months. The estimated 96-month OS was 68%, 81%, 88%, and 97% for patients with DFI of <2, 2-<5, 5-<10, and =10 years, respectively (p<0.001). Similar differences were observed for estimated 96-month DMFS (57%, 69%, 81%, and 92%, respectively; p < 0.001). On multivariable analysis, each 1-year increase in DFI was independently associated with improved OS (HR 0.84, 95% CI 0.77-0.93, p < 0.001) and DMFS (HR 0.87, 95% CI 0.82-0.93, p < 0.001). Higher stage (T1N1 or T2N0), subtype (Luminal B and triple negative), and neoadjuvant chemotherapy receipt for the initial breast cancer diagnosis were also independently associated with OS and DMFS after recurrence, but receipt of hormonal therapy or radiotherapy for the initial cancer diagnosis were not associated with either endpoint.
Conclusion: In a large contemporary cohort of patients with early-stage breast cancer who had IBR, DFI was independently associated with OS and DMFS after IBR. These findings suggest that the timing of recurrence is a meaningful prognostic factor beyond standard clinicopathologic features that may reflect underlying tumor biology. Further research defining the prognostic value of DFI may enable oncologists to integrate DFI into risk-stratification, treatment selection, and patient counseling.