Abstract PS2-03-06: Prevalence and Impact of Treatment-Related Pain on Quality of Life in Brazilian Breast Cancer Patients

Abstract Introduction: Breast cancer (BC) remains the most common malignancy among women and is the fourth leading cause of mortality worldwide. Despite advances in screening, surveillance, and treatment that have improved survival rates, most patients continue to experience treatment-related adverse effects that significantly impact their quality of life(QoL). Objective: This study aims to describe the prevalence and risk factors associated with chronic pain, as well as its impact on QoL, in patients with BC treated at a single institution in Brazil. Methodology: This cross-sectional study included patients with BC who received treatment in the mastology department of Hospital das Clínicas da Universidade Federal de Goiás, Brazil in 2022. Data collected included clinical characteristics (age, menopausal status, comorbidities) and treatment characteristics (type of surgery, radiotherapy, chemotherapy, and treatment toxicity). Standardized questionnaires assessing chronic pain, such as the McGill Pain Questionnaire and the Visual Analogue Scale (VAS), were administered. Statistical analyses were performed using R Studio v 3.6, employing descriptive statistics, Pearson correlation, and regression analyses to evaluate the study data. Results: 122 patients were included in the analysis, with a median age of 55 years. 84% were postmenopausal. Breast reconstruction was performed in 53% of the patients, the majority of whom (92%) underwent immediate reconstruction. Regarding systemic therapy, 51% of patients received neoadjuvant chemotherapy and 29% received adjuvant chemotherapy. Additionally, 81% of the patients received radiotherapy. Lymphedema was present in 20% of the cohort and seroma was reported in 15% of all patients. The total McGill score had a median of 30 (IQR: 22-38). On the Visual Analogue Scale, the median pain intensity was 5.5 (IQR: 3-8). We conducted Wilcoxon rank-sum tests to assess whether pain intensity, measured by the VAS scale, varied according to clinical and treatment-related variables. Patients who underwent mastectomy reported significantly higher pain scores than those who received breast-conserving surgery (p = 0.0088). Higher VAS scores were also observed among patients with lymphedema (p = 0.0069) and those who experienced wound dehiscence (p = 0.026). Interestingly, patients who received radiotherapy reported significantly lower pain intensity compared to those who did not undergo this treatment (p = 0.016). We also examined the association between clinical characteristics and pain perception using the total score from the McGill Pain Questionnaire. Among the variables analyzed, wound dehiscence was significantly associated with higher McGill scores (p = 0.011). Conclusion: Chronic pain is highly prevalent and significantly impairs health-related quality of life in breast cancer patients treated in our cohort in Brazil, especially those with high-risk surgical profiles and comorbidities. Citation Format: R. Macedo Sousa Rahal, H. Garcia Gomes de Andrade, L. Pádua Oliveira, D. Calheiros Campelo Maia, F. Cardoso Marques, C. Dias Caminha Gentile, M. Macambira Noronha, P. Costa Passos, V. Oliveira Costa Filho. Prevalence and Impact of Treatment-Related Pain on Quality of Life in Brazilian Breast Cancer Patients abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS2-03-06.