Abstract P3-07-39: CASCADE study: Treatment and clinical outcomes of metastatic breast cancer by tumor immunophenotypes
Authors: Zamora P , Servitja S , Santaballa A , García J , de Paz L , Plata Y , Garau I , Florian J , Chacón I , de la Haba J , García P , Artime E , Rodríguez-Villanueva J , Velasco A , Martínez E , Segui MA 
Published: May 2016

BACKGROUND: Currently available therapeutic armamentarium for locally advanced and/or metastatic breast cancer (LA/MBC) allows an increasing tailored approach for each of the major tumor immunophenotypes. Nevertheless, there is scarce information about how these subgroups fare and how the alternative therapeutic approaches are actually being used during the disease course. CASCADE is an epidemiological, retrospective, and multicenter study aimed to retrieve demographic and clinical information from a representative cohort of LA/MBC patients treated within the Spanish National Healthcare System.

MATERIALS AND METHODS: Several strategies were used to identify patients diagnosed with LA/MBC for the first time between 01/2007 and 12/2008 in 13 Spanish public hospitals covering nearly 5'000'000 inhabitants (&gt;10% of the national population) and followed throughout their metastatic lifetime until death, lost to follow-up, or until December 2013. Data collected included demographical and clinical information for each line of treatment. Descriptive statistics were applied to analyze the information.

RESULTS: We identified 443 LA/MBC patients. Median age at diagnosis was 59 years (CI95%: 49.5 - 71.6). Significant differences in dropout rates per line of treatment were found according to the tumor intrinsic immunophenotype. Patients reaching a 4th line were: whole study population 38.4%, HER2-/HR+ 42.8%, HER2+/HR- 41.5%, HER2+/HR+ 39.5%, and Triple-negative 31.9%. Median Overall survival (OS) and per line Progression Free Survival (PFS) for each line of treatment by tumor subtype were:

Median OS and per line PFS by tumor subtype Subtype (%)OS (months)PFS (months)PFS (months)PFS (months)PFS (months)PFS (months)Treatment line--1L2L3L4L5LWhole PopulationAll33.57.25.94.33.73.0HER2-/HR+43.838.68.85.84.43.33.0HER2+/HR-12.036.37.46.74.34.03.0HER2+/HR+17.234.411.27.94.95.83.5Triple-negative16.319.04.03.52.43.32.9

Percent use of the four major pharmacological families per line of LA/MBC treatment was:

Pharmacological families used per line of LA/MBC treatmentTreatment line1L2L3L4L5L6L7LChemotherapy75.463.075.979.487.976.178.6Anti-HER219.721.919.420.618.720.921.4Hormone therapy37.939.225.318.811.217.916.7Other targeted therapy13.09.612.212.47.511.914.3

CONCLUSION: Our study identifies differences in OS and PFS among BC immunophenotypes, with Triple-negatives faring the poorest. Among therapeutic families, chemotherapy clearly prevails along the disease lifetime, with hormone therapy being primarily used during the initial lines of treatment.

Citation Format: Zamora P, Servitja S, Santaballa A, García J, de Paz L, Plata Y, Garau I, Florian J, Chacón I, de la Haba J, García P, Artime E, Rodríguez-Villanueva J, Velasco A, Martínez E, Segui MA. CASCADE study: Treatment and clinical outcomes of metastatic breast cancer by tumor immunophenotypes. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-39.