Abstract PS2-02-30: Five-year survival outcomes after systemic therapy in older patients with early-stage triple negative breast cancer at memorial sloan kettering cancer center

Abstract INTRODUCTION: Approximately 15% cases of Triple Negative Breast Cancer (TNBC) are diagnosed in individuals over the age of 70. Older patients remain underrepresented in clinical trials. We conducted a retrospective review of patients to describe the clinical practice patterns and outcomes in patients aged ≥70 years with stage I-III TNBC who were treated at Memorial Sloan Kettering Cancer Center (MSKCC). MATERIAL AND METHODS: Medical records of patients with patients aged ≥ 70 years diagnosed with stage I-III triple negative breast cancer from January 1st, 2015, through December 31st, 2019, were abstracted. Charts were analyzed for patient demographics, cancer stage, pathology reports, surgical and systemic therapy data. Chemotherapy (C) and non-chemotherapy (NC) groups were compared based on baseline characteristics, toxicities, and outcomes. We compared patient characteristics by chemotherapy type using Wilcoxon rank sum test, Pearson’s Chi-squared test, and Fisher’s exact test. Overall Survival (OS), Breast Cancer Specific Survival (BCSS), and Recurrence Free BCSS (RF-BCSS) were examined using Cox proportional hazards models. All statistical analyses were conducted using R. RESULTS: Total 144 patients were included in our data analysis. The median age of participants was 75 years (range 70-96). The number of patients with stage I, II, and III disease was 61 (42%), 66 (46%), and 17 (12%), respectively. NC group was associated with older median age (81 years vs. 74 years (p<0.001)) and a higher rate of referral to geriatric medicine (31% in NC vs. 15% in C, p=0.045). The NC group had significantly higher difficulties in ADLs such as walking (27% vs. 12%, p=0.041), dressing (19% vs. 4.4%, p=0.014), and bathing (19% vs. 4.4%, p=0.014) compared to the C group. NC group also had significantly higher difficulties in IADLs such as meal preparation (27% vs. 3.3%, p<0.001), shopping (30% vs 8.9%, p=0.003), laundry (27% vs. 7.8%, p=0.008), finances (22% vs. 4.4%, p=0.005), handling medicines (16% vs. 3.3%, p=0.018), and doctors’ visits (19% vs. 3.3%, p=0.007). Although C-group was associated with an improved OS (Hazard Ratio (HR) 0.56, 95% CI 0.32-1.00, p=0.049), there was no difference in BCSS (HR 1.00, 95% CI 0.41-2.45, p>0.9) and RF-BCSS (HR 0.68, 95% CI 0.34-1.37, p=0.3) between C- and NC- groups. Doxorubicin-Cyclophosphamide-Paclitaxel (ACT) and Cyclophosphamide-Methotrexate-5-Fluorouracil (CMF) were the most common chemotherapy regimens administered. Compared to ACT, CMF was associated with greater median age (median age 75 vs. 71 years, p<0.001), stage I disease (54% (CMF) vs. 26% (ACT), p=0.027), and higher ADL (28% (CMF) vs. 0% (ACT), p=0.005) and IADL difficulties (28% in CMF vs 4.3% in ACT, p=0.024). Treatment delays and discontinuation rates were 8.7% and 22% patients treated with ACT, and 5.1% and 26% patients receiving CMF, respectively. There was no difference in OS (HR 1.01, 95% CI 0.37-2.73; p>0.9), BCSS (HR 1.26, 95% CI 0.40-3.97; p=0.7), and RF-BCSS (HR 1.25, 95% CI 0.44-3.51; p=0.7) in patients receiving ACT versus CMF. CONCLUSIONS: In our single institutional experience, we observed that two-thirds of older patients with early-stage TNBC received systemic polychemotherapy. C-group had an improved OS but not BCSS and RF-BCSS, a finding likely driven by non-oncological factors, with NC being a frailer group of patients with other competing causes of mortality. ACT and CMF were the most common regimens used. Use of CMF was associated with age ≥75, stage I disease, ADL/IADL difficulties, and adjuvant setting. We observed no difference in survival outcomes between the two chemotherapy regimens. CMF remains an efficacious option and a potentially viable alternative to ACT in TNBC, especially in the setting of early stage and advanced age. Citation Format: J. Singh, A. Kulkarni, F. Ehrich, C. White, Y. Chen, K. Alexander, A. Shahrokni, M. Robson, L. Norton, D. Lake. Five-year survival outcomes after systemic therapy in older patients with early-stage triple negative breast cancer at memorial sloan kettering cancer center [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS2-02-30.