Triple negative apocrine breast carcinoma has better prognosis despite poor response to neoadjuvant chemotherapy

Background: Apocrine carcinoma is a rare subtype of invasive ductal breast cancer that shows apocrine differentiation and largely with triple negative immunohistology. Triple negative breast cancers are known to have a more aggressive clinical course. However, unlike the most other types, it is reported that triple negative apocrine carcinoma has a better prognosis. Due to scarcity of reported studies, our knowledges for its clinical behavior, prognosis and response to therapy are very limited. Methods: : In this study, we retrospectively retrieved 41 triple negative apocrine carcinoma cases from our breast cancer database with an average follow up 32.8 months. Results: : It was found that triple negative apocrine carcinoma had poorer response to neoadjuvant therapy, but better prognosis compared with other non-apocrine types of triple negative breast cancer. Meanwhile, triple negative apocrine carcinoma has a low proliferative nature as indicated by its low Ki67 index. Analysis of SEER database showed that chemotherapy did not improve breast cancer specific survival in TNAC patients. Conclusions: : Our results suggest that triple negative apocrine carcinoma is a special subtype of triple negative breast cancer for which de-escalation of chemotherapy should be considered.