Abstract
BACKGROUND: Breast cancer is the most commonly diagnosed malignancy among women worldwide and a leading cause of cancer-related morbidity. As treatment advances have improved survival rates, symptom management has become a key component of comprehensive cancer care. Cancer-related symptoms often present in clusters rather than in isolation, potentially amplifying patient discomfort and negatively impacting quality of life. Identifying stage-specific symptom cluster patterns may provide critical insights for developing personalized supportive care strategies. This study aimed to identify and compare the prevalence, intensity, and discomfort of symptom clusters in women with Stage I and Stage III nonmetastatic breast cancer. METHOD: This cross-sectional study included 87 women aged > 18 years with histopathological diagnoses of Stages I-III breast cancer, undergoing any phase of antineoplastic treatment at an oncology hospital in Brazil. Symptoms were assessed using the Memorial Symptom Assessment Scale (MSAS). The bootstrap resampling method was used to estimate 95% confidence intervals (CIs) for prevalence ratios (PRs) of MSAS symptoms, stratified by cancer stage. Symptom clusters were identified using hierarchical and k-means clustering analyses. RESULTS: Among Stage I patients, the most prevalent symptoms were pain (68.6%), worrying (62.8%), difficulty sleeping (62.8%), and fatigue (60.8%). In Stage III patients, the most frequent symptoms were pain (72.0%), fatigue (66.7%), worrying (63.9%), and dry mouth (50.0%). Stage I patients had a higher prevalence of difficulty concentrating (PR = 1.50; p = 0.015), shortness of breath (PR = 1.51; p < 0.001), feeling sad (PR = 1.41; p = 0.002), and hair loss (PR = 1.60; p = 0.037) compared to those with Stage III disease. Four clusters were identified for Stage I patients-neuropsychological, gastrointestinal, neurocognitive, and psychological-and for Stage III patients-psychoneurocognitive, gastrointestinal, chemotherapy-related, and neurocognitive. CONCLUSION: These findings highlight the heterogeneity of symptom experiences in women with nonmetastatic breast cancer, with distinct cluster profiles emerging at different disease stages. Understanding stage-specific symptom patterns may inform more personalized and targeted supportive care strategies to improve quality of life and clinical outcomes in this population.