Economic Burden of Disease Recurrence in Elderly Patients With Human Epidermal Growth Factor Receptor 2-Negative (HER2–) Early Breast Cancer (eBC)

OBJECTIVES: Many patients with HER2– eBC treated with standard of care experience recurrent disease. To advance the understanding of the economic burden of recurrence, this study quantified the impact of recurrence on healthcare resource utilization (HRU) and costs in elderly patients with HER2– eBC.

METHODS: Patients aged ≥66 years with Stages I–III HER2– breast cancer (BC) were identified from SEER-Medicare data (2010–2019). BC recurrence was identified using a claims-based algorithm developed with clinical input. All-cause and BC-related HRU (per-patient-month) and monthly healthcare costs were estimated from the BC recurrence date for recurrent patients and from an imputed index date for non-recurrent patients using frequency matching. HRU and costs were compared between recurrent and non-recurrent patients with hormone receptor-positive (HR+) and triple negative BC (TNBC) using multivariable regression models.

RESULTS: Of 28,655 patients (HR+ BC: 90.4%; TNBC: 9.6%), 8.5% experienced recurrence (median follow-up: 4 years). Overall, recurrent patients had more advanced disease (Stage II/III: 73.7% vs. 34.0%) and higher-grade tumors (Grade III/IV: 40.6% vs. 18.0%) at diagnosis than non-recurrent patients. Recurrence in HR+ and TNBC was associated with higher rates of all-cause hospitalizations (incidence rate ratio [IRR]: 2.84 and 3.65), emergency department (ED) visits (IRR: 1.75 and 2.00), and outpatient visits (IRR: 1.46 and 1.55) than non-recurrence (all p<0.001). Likewise, recurrent disease was associated with higher rates of BC-related HRU, particularly for ED visits in HR+ BC (IRR: 4.24; p<0.001) and hospitalizations in TNBC (IRR: 11.71; p<0.001). Patients with recurrent HR+ and TNBC incurred higher all-cause healthcare costs (cost difference [CD]: $3,988 and $4,651) and BC-related healthcare costs (CD: $3,743 and $5,819).

CONCLUSIONS: Our findings shed light on the significant economic burden of recurrent disease in HER2– eBC and underscore the unmet need for early identification of high-risk patients and optimization of therapies that mitigate recurrence in this population.