Background: This study aimed to assess breast cancer awareness among patients undergoing active treatment for breast cancer at Day Hospital, assess their quality of life (QoL), and explore the association between minor knowledge of the disease and higher levels of anxiety.

Methods: This prospective observational study included patients with breast cancer undergoing active treatment at the Instituto Português de Oncologia Coimbra. The EORTC QLQ-C30, QLQ-INFO25, and Anxiety and Depression Scale (HADS) were completed, and demographic and clinical data were collected and processed using SPSS.

Results: In total, 188 patients with breast cancer were included. A vast majority had a positive perception of their QoL, with a higher average value compared to “cognitive functioning” (X=77.22±22.53), “social functioning” (76.86±25.41), and “physical functioning” (75.67±17.24).

Regarding the information received, an overall “score” below the “cut-off line” (47.96±14.40) was observed. When evaluating “satisfaction” in isolation, the average value for “satisfaction with the information received” was 53.55±23.99, and patients perceived that the information received was beneficial to them (67.38±23.87) and did not wish to have received less information (99.47±7.29).

With decreased functionality, higher levels of depression and anxiety were observed (p<0.0001).

Regarding “information related to illness and anxiety/depression”, it was noted that as satisfaction with information decreased, patients tended to have higher levels of anxiety/depression (p<0.013).

Conclusions: It is necessary to create dedicated spaces for information and clinical clarification, with regular assessments of patients’ perceptions. The information provided must be reinforced through written or digital support, or brochures.

Patients completed the EORTC QLQ-C30 (version 3), EORTC QLQ-INFO25, and Hospital Anxiety and Depression Scale (HADS), validated for Portuguese.

All statistical analyses were performed using IBM IBM-SPSS 23.0 program (Statistical Package for the Social Sciences) for Windows. Descriptive and analytical statistics were used for data analysis. Absolute and percentage frequencies were determined according to the characteristics of the variables under study (measures of central tendency or location: mean, mode, and median; measures of variability or dispersion: coefficient of variation and standard deviation; and measures of asymmetry and flatness). Regarding inferential statistics, non-parametric statistics were used because the requirements for the use of parametric statistics were not met. Thus, the Kolmogorov- Smirnov test was used to study the normality of the distribution of variables, ​​and the Levene test was used to study the homogeneity of the variances. For non-parametric statistics, Spearman´s correlation was used. In the statistical analysis, the following significance values ​​were used: p<0.05, statistically significant difference; p ≥ 0.05, non-significant statistical difference.