A population‐based comparison of treatment patterns, resource utilization, and costs by cancer stage for Ontario patients with triple‐negative breast cancer

BACKGROUND: There have been few publications exploring the characteristics, treatment pathways, and health‐care costs by stage in patients with a triple‐negative breast cancer (TNBC) phenotype. METHODS: Data from a publicly funded health‐care system in Ontario were assessed. Baseline characteristics, treatment patterns, and health‐care costs were descriptively compared by cancer stage (I‐III vs IV) for adult women diagnosed with invasive TNBC between 2012 and 2016. Resource use was multiplied by unit costs for publicly funded health‐care services to calculate health system‐related costs. RESULTS: A total of 3271 cases were identified, 3081 with stage I‐III and 190 with stage IV TNBC. Baseline characteristics were aligned with previous reports. Surgery was the most common treatment among patients with stage I‐III disease (n = 2979, 96.7%); 557 (18.7%) received neoadjuvant therapy (NAT) and 1974 (66.3%) received adjuvant therapy (AT), the latter at a median of 44 days postsurgery, and 2446 (79.4%) in the stage I‐III cohort received radiation. Treatment for metastatic TNBC included surgery in 48 (25.3%), systemic therapy in 138 (72.6%), and radiotherapy in 112 (58.9%) patients. Top drug regimens included anthracyclines/taxanes. Annual per‐patient health care costs were four times higher for stage IV vs. stage I‐III TNBC. CONCLUSION: Per‐patient costs were higher in metastatic TNBC, despite a less frequent use of all treatment modalities compared to early TNBC. Treatment patterns were aligned with the options available at the time; however, neoadjuvant treatment rates were low.