Overall survival and associated factors in women with metastatic breast cancer treated with trastuzumab at a public referral institution

OBJECTIVE: To characterize associated factors and overall survival of women with metastatic breast cancer treated with trastuzumab after its incorporation into the SUS, and additionally to present the direct costs of this technology. METHODS: This is a retrospective cohort, based on data from computerized medical records from one of the units of the National Cancer Institute (INCA), in Rio de Janeiro-RJ, Brazil. Women with HER-2 positive metastatic breast cancer undergoing trastuzumab treatment from September 2017 to August 2018 were included. Overall survival was estimated using the Kaplan-Meier method and compared between groups using the log-rank test. RESULTS: 136 women were selected, whose median age at diagnosis was 51 years (range: 21–81 years). The median OS was 43.63 months (95%CI 33.92–53.34). It is observed that the median OS for the population already diagnosed with metastatic disease (stage IV) was significantly lower than for patients diagnosed in stages I-III (37.43 months vs. 48.6 months, p<0, 01). Women without previous use of trastuzumab had a higher median OS than patients pretreated with trastuzumab (45.16 months vs. 40.73 months, p<0.01). CONCLUSION: Trastuzumab improves survival in HER-2 positive metastatic breast cancer. Brain and multiple metastases are associated with a worse prognosis. It is essential to avoid advanced staging and perform surgical treatment, with emphasis on radical mastectomy. The SUS must adopt policies and strategies for early diagnosis and guarantee access to trastuzumab, considering its high cost.