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.