A comparison between young and old patients with triple-negative breast cancer: biology, survival and metastatic patterns

PURPOSE: To determine the biology, recurrence rate, metastatic patterns and survival times in primary triple-negative breast cancer (TNBC) with focus on the comparison between younger and elderly patients. METHODS: Patients with primary TNBC stage I–IV diagnosed from 2007 to 2015 were identified and information on tumor biology, stage, treatment, recurrences and death recorded. RESULTS: A total of 524 patients, median age 60 years (range 24–94) with a median follow-up of 55 months (range 0–129) were identified. Stage was similar in younger (< 40 years) (n = 58) and older (> 74 years) (n = 96) patients (p = 0.37). A statistically significant difference was found concerning histopathologic grade (p = 0.006) and Ki67 (median 80% versus 70%; p = 0.002) but not for LVI (p = 0.9) with more aggressive tumors among younger patients. Adjuvant/neoadjuvant chemotherapy was more frequently given to younger compared with older patients (96% versus 12%; p = 0.0005). Only brain (p = 0.016) and liver (p = 0.047) metastases were more often registered among younger patients while other locations were similar. Shorter survival times, recurrence-free survival (RFS), distant disease-free survival (DDFS) and breast cancer-specific survival (BCSS) were found in the older group, although not after adjusting for adjuvant/neoadjuvant chemotherapy. Most deaths (68%) in the older group were caused by TNBC. When comparing patients > 75 years (n = 92) with ≤ 75 years (n = 432), a worse outcome among older was also observed: RFS (p = 0.00012), DDFS (p = 0.00041), BCSS (p < 0.0001) and survival following distant metastasis (p = 0.0064) CONCLUSIONS: Primary TNBC in younger patients is more often of poor differentiation grade and highly proliferative compared with older patients. The majority of older patients still have grade III tumors with a Ki67 > 60% and outcome is poor. Few older patients in our study were treated with chemotherapy both in adjuvant and palliative setting, underlining the need for more prospective trials and treatment options suitable for this patient population.