Level of education, background and clinical stage as prognostic factors according to RMST function in patients with early and locally advanced breast cancer: a single institution experience from Romania

BACKGROUND AND AIMS: Our aim is to examine the relationship between the level of education, background, tumor size and lymph node status on the treatment outcome in a group of patients with early and locally advanced breast cancer (BC) by using the restricted mean survival time (RMST), which summarizes treatment effects in terms of event-free time over a fixed period of time. METHODS: We evaluated the prognostic values in 143 patients treated for early BC at Elias University Emergency Hospital, Bucharest, Romania and followed up for a maximum of 36 months. The protocol was amended to include the levels of education (gymnasium, high school, or university), the background (urban or rural) and the clinical stage (primary tumor (T) and regional nodes (N)). The methodology consisted in using a Kaplan–Meier analysis and RMST for the entire sample and Cox regression, for the variables with statistical influence. The principal endpoints of the study were overall survival (OS) and progression free survival (PFS). RESULTS: The level of education had impact both on RMST OS (35.30 vs. 26.70) and death HR (hazard ratio) in the group of patients with general school level, compared with those with graduated university. In this study, the urban or rural background did not impact the outcome, probably because in this study we included predominantly patients from urban areas (83%). Although clinical tumor size measurements did not impact the outcome, the clinical staged lymph node influenced both OS (p=0.0500) and PFS (p=0.0006) for the patients with palpable or imaging proof of lymph node involvement of station 2 or 3. CONCLUSIONS: RMST provides an intuitive and explicit way to express the effect of those risk factors on OS and PFS in a cohort of early breast cancer patients. Low level of education and high-grade clinical lymph node status negatively influences the outcome of this cohort of BC patients.