OBJECTIVES: Patients with early-stage (I/II/IIIa) hormone receptor positive, human epidermal growth factor receptor-2 (HER2) negative invasive breast cancer with 1-3 positive lymph nodes (N1) often undergo surgical excisions followed by adjuvant chemotherapy (ACT). Many of these patients, e.g., post-menopausal women, have no benefit from ACT and receive unnecessary treatment that is costly and often associated with short and long-term adverse effects (AEs). Gene expression profiling (GEP) assays, such as the 21-gene breast recurrence score® (21-gene), can be used to identify patients at higher risk for recurrence and who may benefit from ACT. However, the budgetary consequence of using 21-gene versus no GEP in the Netherlands is currently unknown and therefore here assessed using a cost-consequence model.

METHODS: A validated model for node negative (N0) breast cancer patients was used as the basis to create the N1 model, which was revalidated by a clinical expert. The model compared the deterministic costs and consequences of using 21-gene versus no GEP, and subsequent ACT use with corresponding costs for chemotherapy, treatment of AEs, productivity losses, GEP testing, and treatment of recurrences, according to Recurrence Score® result. The model time horizon was 5 years. Data from the literature were used to populate the model.

RESULTS: Using 21-gene resulted in mean cost-savings of €11,907 per patient and €8,970,383 over 5 years for the Dutch healthcare system when compared to no GEP. 21-gene resulted in fewer patients receiving ACT and fewer AEs, sick days, and hospitalisations. The proportion of patients receiving ACT was mainly responsible for driving up the costs.

CONCLUSIONS: Using 21-gene assay as a diagnostic test in post-menopausal N1 breast cancer patients results in overall cost-savings compared to no GEP. Implementing 21-gene in this population can prevent unnecessary overtreatment, which leads to less clinical and economic burden on the patient and Dutch healthcare system.