Breast cancer-specific mortality in early breast cancer as defined by high-risk clinical and pathologic characteristics.

To investigate breast cancer-specific mortality by early breast cancer (EBC; Stages I-IIIC) subtype; incidence of high-risk indicators for recurrence (defined in monarchE trial); and mortality risk difference by those who did/did not meet these criteria. Analyses included patients with initial EBC diagnosis between 2010-2015 from Surveillance, Epidemiology, and End Results (SEER) data (n = 342,149). Cox proportional hazards models and Kaplan-Meier estimates examined mortality among 228,031 patients, by subtype (hormone receptor [HR]-positive [+], human epidermal growth factor receptor-2 [HER2] negative [-]; triple negative [TNBC]; HR+, HER2+; HR-, HER2+). Incidence and mortality among patients who did/did not meet monarchE clinicopathological high-risk criteria were examined. Among patients with HR+, HER2- EBC, histologic Grade 3 (vs. Grade 1) was the most influential factor on mortality (hazard ratio, 3.61; 95%CI, 3.27, 3.98). Among patients with TNBC, ≥4 ipsilateral axillary positive nodes (vs. node negative) was the most influential factor on mortality (hazard ratio, 3.46; 95%CI, 2.87, 4.17). For patients with HR-, HER2+ or HR+, HER2+ EBC, tumor size ≥5 cm (vs. <1 cm) and ≥4 ipsilateral axillary positive nodes were the most influential factors on mortality. The 60-month mortality rate for the 12% of patients within the HR+, HER2- EBC group meeting monarchE clinicopathological high-risk criteria was 16.5%, versus 7.0% (Stage II-III and node positive) and 2.8% (Stage I or node negative) for those not meeting criteria. The 60-month mortality rate for patients with TNBC was 18.5%. Mortality risk and the relative importance of risk factors varied by subtype. monarchE clinicopathological high-risk criteria were associated with increased mortality risk among patients with HR+, HER2- EBC. Patients with HR+, HER2- EBC, and monarchE clinicopathological high-risk criteria experienced risk of mortality similar to patients with early TNBC. These data highlight a high unmet need in this select patient population who may benefit most from therapy escalation.

Déclaration de conflit d'intérêts

The authors have read the journal’s policy and report the following conflicts: David Nelson and Jacqueline Brown are employees of a commercial company: Eli Lilly and Company. They are also minor shareholders of a commercial company: Eli Lilly and Company. Michael Method is a former employee of a commercial company: Eli Lilly and Company. Michael Method is a current employee of a commercial company: Immunogen. Aki Morikawa is an employee of the University of Michigan. Aki Morikawa reports receiving institutional research funding from the following commercial companies: Eli Lilly and Company, Seattle Genetics, Eisai/H3B, Novartis, Takeda, Pfizer, and Molecular Templates Inc.; she also reports consulting with Eli Lilly and Company and serving on an advisory board for Seattle Genetics. This does not alter our adherence to PLOS ONE policies on sharing data and materials.