Impact of Detection Method and Age on Survival Outcomes in Triple-Negative Breast Cancer: A Population-Based Cohort Analysis.

ABSTRACT

BACKGROUND: Most investigations have compared triple-negative breast cancer (TNBC) to non-TNBC to elucidate clinical or epidemiologic differences between subtypes. We examined a contemporary cohort of patients with primary TNBC by detection and age at diagnosis within a population-based breast screening program to examine survival outcomes. PATIENTS AND METHODS: All women with a diagnosis of primary TNBC between January 1, 2005, and December 31, 2012, in Nova Scotia, Canada, were included. Clinicopathologic and detection variables were abstracted from the Nova Scotia Breast Screening Program. Patient charts were abstracted for adjuvant therapies and survival outcomes, supplemented by provincial vital statistical data. RESULTS: A total of 412 patients comprised the study population, with almost half aged over 60 years (46.3%) and 30.2% having screen-detected disease. There were no significant differences in prognostic variables between age groups. Younger patients were more likely to receive adjuvant chemotherapy (96.3% ≤ 49 years vs. 31.2% ≥ 70 years), but there were no differences in disease-free or breast cancer-specific survival between the age groups. For those with disease recurrence, median time to recurrence and death was shorter for younger patients (17 vs. 26 months, 16 vs. 33 months respectively; age 40-49 vs. 70+). Those with screen-detected disease had better disease-free, breast cancer-specific, and overall survival outcomes. CONCLUSION: Detection method may play a role in TNBC survival outcomes, thus supporting novel screening strategies for TNBC. Shorter time to survival events in the younger patient groups suggests that TNBC is a clinically heterogeneous disease despite similarities in prognostic factors across age.