e11621 Background: Breast cancer(BC)is the most frequent neoplasm in women. Triple negative phenotype(TNP)is characterized by lack of expression of estrogen receptor(ER),progesterone receptor(PgR) and Her-2, and it is associated with a worse prognosis. Patients and Method: We conducted a retrospective study of consecutive cases of BC with TNP by immunohistochemistry(IHC),treated in our center within the last 5 years,with primary endpoint of analyzing the disease-free-survival (DFS).Second endpoints of the study were overall survival (OS),place of the first recurrence and cause of death. Results: After reviewing 295clinical histories of localized BC(with available ER,PgR and Her-2 by IHC),we found a total of 24 patients(p)with TNP(Prevalence=8.14%[95CI%: 5.3–11.9%].Ps characteristics:median age=50 years(26–74);premenopausal=55%;tumor grade:G3=40%;G2=60%;85.7% had high Ki-67(>40%);63.2% had stageIIB-III;median tumoral size=2.1cm;node positive=80%(25% with 4 or more positive nodes);96% was ductal carcinoma;56.5% was treated with mastectomy;78% with radiotherapy.Eighty-three percent of ps were treated with neoadjuvant and/or adjuvant chemotherapy with anthracyclines and taxanes:34.8% with adjuvant chemotherapy (AC60/600x4–>Paclitaxel-175x4);21.7% with neoadjuvant ATX(doxorubicin, docetaxel and capecitabine);and 26.1% with neoadjuvant AT(doxorubicin and docetaxel), and only 4 ps with adjuvant CMFx6.With a median follow-up of 36 months(m),median DSF was 42 m(95%CI: 33–51),and the probability of DSF at 3y was 67%.Median OS was 82m(95%CI: 41–123),with a probability at 5y of 52%.Thirty-eight percent(9/24)of ps had an event(3 recurrences and 6 deaths),and 100%of the deaths were caused by tumoural progression. Deaths according to the chemotherapy:75%(3/4 patients)in CMF group vs 15%(3/20)in anthracycline and taxane group(P=0.040; Fisher test).Mainly localization of the first recurrence was multiple in the 44.4%of the cases, followed by the liver(22.2%),lung(11.11%),bone(11.11%)and brain (11.11%). Conclusions: Our study confirmed the worse prognosis associated with triple negative BC.This subtype of BC must be treated with the most active cytostatic drugs in the adjuvant setting. No significant financial relationships to disclose.