Triple‐negative breast cancer in the elderly: Prognosis and treatment

Our objective is to characterize treatment of triple‐negative breast cancer (TNBC) in older patients and measure mortality risk relative to younger women. We conducted a retrospective cohort study analysis of patients presenting with primary TNBC, age 25‐93, stage I‐III from 1990 to 2014, identified and tracked by our registry (n=771). Clinical characteristics were chart abstracted at diagnosis and follow‐up. The Kaplan–Meier method was used to measure disease‐specific survival (DSS) by age with Cox regression modeling for relative contribution of patient and clinical characteristics. Of patients, 80% were <65 years (n=612), 13% were 65‐74 years (n=100), and 7% were 75 and older (n=59). Older women presented more often with lower stage BC (stage I: 31% age <65, 48% age 65‐74, 39% age 75+; P=.014). All three age groups were equally likely to have radiation therapy (77%) but older patients were less often treated with adjuvant chemotherapy (<65=95%, 65‐74=76%, 75+=39%; P<.001). Mean follow‐up was 7.34 years and did not differ by age. Five‐year DSS was equivalent across the three age groups (<65=85%, 65‐74=90%, 75+=83%, P=.322). In Cox regression analysis controlling for stage, histologic and nuclear grade, diagnosis year, radiation and chemotherapy treatment, age was not significantly associated with disease‐specific mortality. TNBC survival appears equivalent by age despite less aggressive treatment in patients 75 years and older. This may be a result of lower stage at diagnosis and decreased disease virulence resulting in comparative survival despite less treatment.