Abstract P1-13-06: Does histological subtype play a role in treatment decision-making for hormone receptor positive metastatic breast cancer? A study of the Southeast Netherlands breast cancer consortium

IntroductionBreast cancer is a heterogeneous disease with distinct biological subtypes. Invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) are the two most frequent histological breast cancer subtypes. With this study, we aimed to provide insight into the role of histological subtype on the characteristics, choices with respect to systemic therapy in daily practice and outcome of patients with metastatic breast cancer.Patients and methodsWe analyzed 815 patients diagnosed with metastatic breast cancer in eight hospitals between 2007 and 2009. All hormone receptor (HR) positive patients with either IDC or (mixed) ILC were included. Patient and tumor characteristics, outcomes and treatment data were collected. Survival curves and time to first palliative systemic therapy (either chemotherapy or endocrine therapy) were estimated using the Kaplan-Meier method and compared using log-rank tests. To explore the association of palliative systemic therapy with the survival of patients with metastatic breast cancer a Cox proportional hazards model was performed with palliative chemotherapy and endocrine therapy as a time-dependent covariates.ResultsA total of 568 patients with HR-positive tumors were included; 437 with IDC and 131 with (mixed) ILC. Patients with ILC were older at diagnosis of primary breast cancer, had larger primary tumors and more node-positive disease compared with IDC. Median survival was not different between the subtypes (29 months for ILC and 2...

Source: Cancer Research - February 18, 2016 Category: Cancer & Oncology Authors: Lobbezoo, D., Truin, W., Voogd, A., Roumen, R., Vreudgenhil, G., Dercksen, M., van den Berkmortel, F., Smilde, T., van de Wouw, A., van Kampen, R., van Riel, J., Peters, N., Peer, P., Tjan-Heijnen, V. Tags: Poster Session Abstracts Source Type: research