Abstract
PURPOSE: This study aimed to assess neoadjuvant (neo), post-neo, and adjuvant (adj) treatment (tx) patterns, recurrence rates, and the impact of recurrence timing on the cumulative cost burden among HER2+ early breast cancer (eBC) patients. METHODS: Merative™ MarketScan(®) Databases were used to identify adults newly diagnosed with eBC between 1/1/2017-9/30/2022 with ≥1 HER2 targeted treatment following BC date. Surgery within a year of the BC date delineated neo and post-neo/adj periods before and after the surgery date. Recurrence was reported during the post-surgery period and was defined as evidence of additional chemotherapy treatment, metastasis, or end-of-life care. Generalized linear model (GLM) (gamma distribution and log link) was used to assess the impact of disease recurrence on cumulative 3-year total all-cause costs during the post-surgery period. RESULTS: A total of 3745 patients with HER2+ eBC were included in the study (mean age 53.7 yrs): 57.4% (n=2151) with adj tx only, 40.2% (n=1504) with neo and post-neo tx, 1.9% (n=70) with surgery only, and 0.5% (n=20) neo tx only. During follow-up (median duration post-surgery: 2 years), the rate of first recurrence was highest for surgery only (70.0%) and similar for adj only (16.0%) and neo and post-neo tx (14.3%) cohorts. GLM showed that the cumulative cost burden following surgery was higher among patients who experienced the first recurrence in <12 months vs no recurrence ($348,834 vs $265,279). Patients with chemo only as adj tx had a higher cumulative cost burden (Risk Ratio [RR] 1.28; p <0.001) than those with HER2 targeted treatment; and patients with neo tx had a lower cost burden (RR 0.85, p <0.001) compared with those with no neo tx. CONCLUSION: Delays in recurrence were associated with lower cumulative cost burden. Study findings highlight that the appropriate use of more effective HER2 targeted treatments that delay the time of first recurrence in neoadjuvant and adjuvant settings may improve patient outcomes and reduce the long-term healthcare burden associated with BC.