Characteristics of triple-negative metastatic breast cancer among older adults: A population-based analysis.

Abstract

1092 Background: The prognosis for women with metastatic breast cancer (MBC) is worse for those who have triple negative MBC (TNMBC). Few reports have examined TNMBC in an elderly population. The US National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database provides information on estrogen receptor (ER) status and progesterone receptor (PR) status but does not record human epidermal growth factor receptor 2 (HER2) status, making identification and analysis of TNMBC patients challenging. Methods: Females over the age of 65 with stage IV breast cancer were identified in the SEER-Medicare database. Patients with a prior history of breast cancer were excluded. Those who were (1) ER negative, (2) PR negative, (3) had an administrative claim for HER2 test, and (4) did not receive trastuzumab were classified as potential TNMBC (p-TNMBC). Results: Of 1,755 MBC patients who met the inclusion/exclusion criteria, 313 (17.8%) were p-TNMBC. p-TNMBC were younger than other MBC (76.0 vs. 77.6 years, p<0.01). The proportion of p-TNMBC among African-American women was higher than in non-African-American women (22.2% vs. 17.2%; p=0.06). Compared to other MBC, p-TNMBC were more likely to have consulted with a medical oncologist (83.1% vs. 72.6%, p<0.01). Unadjusted median survival time was 7 months for both p-TNMBC and other MBC patients. Comparisons were similar when we excluded 218 patients who were classified as other MBC (not p-TNMBC); these MBC women were ER negative and PR negative but HER2 status was questionable since they did not have an administrative claim for a HER2 test and did not receive trastuzumab. Conclusions: As defined in this study, TNMBC occurred in approximately 18% of elderly MBC patients. TNMBC patients were younger and were more likely to have consulted a medical oncologist. TNMBC rates were slightly higher among African-Americans than other races. Unadjusted median survival was similar among p-TNMBC and other MBC. Knowledge of characteristics of TNMBC in the “real world” contributes to the understanding of the epidemiology and need for research and development of treatment strategies. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration sanofi-aventis Amgen, Bayer, Genentech, Lilly, Novartis, Pfizer, sanofi-aventis sanofi-aventis Pfizer, sanofi-aventis Novartis, Pfizer, sanofi-aventis