Dados do Trabalho

Título

PLATINUM-BASED CHEMOTHERAPY FOR HORMONE RECEPTOR-POSITIVE HER2-NEGATIVE METASTATIC BREAST CANCER: 10-YEAR DATA FROM A BRAZILIAN CANCER CENTER

Introdução

Platinum-based chemotherapy (CT) regimens are active in triple-negative breast cancer, with overall response rates around 50%. Evidence of activity is scarce for hormone receptor (HR)-positive breast cancer.

Objetivo

We evaluated the effectiveness of platinum-based CT for HR-positive HER2-negative metastatic breast cancer (mBC).

Método

HR-positive HER2-negative mBC patients who have received at least 1 dose of platinum-based CT from April/2009 to May/2020 in a single Brazilian cancer center had their medical records retrospectively analyzed. Clinical and demographic data, treatment, and outcomes were collected. Primary endpoint was the clinical benefit rate (CBR) at 3-month. Secondary endpoints were overall response rate (ORR), progression-free survival (PFS) and overall survival (OS).

Resultado

Among 394 patients: 391 female, median age 52.3 years, 53% premenopause, 34% metastatic at diagnosis, and 64.8% ECOG-PS 0-1 by the time of platinum-based CT initiation. Although tests for hereditary breast and ovarian cancer (HBOC) were not available, 31% of patients met criteria. In addition, 87.1% was invasive ductal carcinoma, 94.2% estrogen receptor >10% positive, 81.9% had visceral disease, and 31.7% palliative CT naive; 69.3% received cisplatin plus gemcitabine, 10.9% a single-agent platinum-based CT, and 19.1% started CT during hospitalization. CBR at 3-month was 39.7% in the overall population, 47.2% when first-line platinum-based CT, and 36.1% when subsequent CT line (P=0.03). ORR was 33.6% in first-line platinum-based CT and 18.8% in subsequent CT line. Median PFS and OS were 3.1 months (95%CI 2.7–3.7) and 9.2 months (95%CI 7.4–10.1), respectively. 1-year OS rate was 38.2% (95%CI 33.1–43.3). Favorable prognostic factors for 3-month CBR were age <60 years (HR 0.56, 95%CI 0.34-0.92, P=0.02), ECOG-PS 0-2 (HR 0.32, 95%CI 0.16-0.64, P=0.001), and having criteria for HBOC syndrome (HR1.60, 95% CI 1.03-2.47, P=0.03). Worse 3-month CBR were seen when platinum-based CT started while hospitalized (HR 0.55, 95%CI 0.31-0.96, P=0.03), as subsequent line (HR 1.58, 95% CI1.02-2.43, P=0.03), and in single-agent regimen (HR 2.78, 95%CI 1.24-6.23, P=0.01).

Conclusão

Despite data show some activity of platinum-based CT for HR-positive HER2-negative mBC, especially as first-line CT, ORR was lower than historically observed in TNBC. Platinum-based CT was associated with poor PFS and OS outcomes. Age <60 years, ECOG-PS 0-2, and having criteria for HBOC syndrome were favorable prognostic factors for 3-month CBR.

Palavras-chave

Metastatic breast cancer; Platinum chemotherapy; Hormone receptor-positive