OBJECTIVES

: The objective of this study is to describe treatment patterns and prognostic factors of patients with advanced or metastatic HR+/HER2- breast cancer in Argentina.

METHODS

: Patients with HR+/HER2- locally advanced or metastatic breast cancer who received endocrine therapy (ET), chemotherapy (CHT) or radiotherapy from 2013 to 2018 were selected from the Instituto de Especialidades Médicas clinical database, which includes individuals covered by the social security. Information collected included clinical stage, treatment, response to treatment and survival. Analysis was conducted stratified by initiation of treatment before or after January 2016.

RESULTS

: 230 patients were included; 32 had started treatment after January 2016. Mean age was 56.4 (SD 11.9) years. In the group that started any treatment after 2016, 31% received CDK4/6 inhibitors, 76% ET and 52% CHT as first-line therapy (66% received more than one treatment). The most prescribed combination was palbociclib with letrozole (21%). The most prescribed first-line CHT was paclitaxel (40%) and doxorubicin (40%). In second-line therapy, CHT increased to 60%. In those patients who started treatment before 2016, first line therapies were CDK4/6 inhibitors 4%, ET 62% and CHT 61% (39% of those who received two or more treatments). The most frequent first-line CHT was paclitaxel (33%) and the most frequent ET was anastrozole (46%). Sensitivity to hormonotherapy (defined as more than 36 months from the end of ET to beginning of first-line, 20% of all cases) and resistance to previous hormonotherapy (less than 24 months from beginning of ET to beginning of first-line or less than 6 months from beginning of hormone therapy first-line and second-line, 23.0% of cases) were identified as relevant prognostic factors for survival.

CONCLUSIONS

: Treatment patterns for advanced or metastatic breast cancer in Argentina are highly heterogeneous and have experienced substantial changes during the last years. The high CHT use indicates an unmet need for care.