Age-related differences in presentation and outcomes of breast cancer: A prospective, comparative study of Colombian patients younger and older than 40 Years

ABSTRACT Background: Breast cancer incidence is rising in Latin America, with 17,018 cases reported in Colombia in 2022. Although predominant in women > 40 years, the disease is notably more aggressive in younger patients. Objectives: The primary objective was to compare health outcomes (stage at diagnosis, progression, and survival) between patients with breast cancer ≤ 40 and > 40 years. Secondary objectives included describing clinical characteristics, evaluating differences in recurrence, and comparing the one- and two-year overall survival by stage and molecular subtype. Materials and Methods: Sociodemographic and clinical data were collected from institutional records. Tumor stage was assigned using the TNM 8 th edition, and molecular subtypes by immunohistochemistry. Group comparisons used the Chi-square or Fisher’s exact test for categorical variables and the Mann–Whitney U test for continuous variables. Survival was estimated with Kaplan–Meier curves and compared using the log-rank test. Results: Patients aged ≤ 40 years showed a higher prevalence of advanced-stage tumors (80%, n = 32 vs. 50.6%, n = 150), predominance of Luminal B subtype (70%, n = 28 vs. 48.3%, n = 143), and more frequent neoadjuvant chemotherapy (85.7%, n = 30 vs. 59.6%, n = 154). Overall survival was 92.1% at one year and 84.2% at two years, with a significant difference between early-stage (99.0%) and advanced cases (70.0%). Conclusion: Age modifies breast cancer presentation and early outcomes, with younger women demonstrating more aggressive clinical profiles. This emphasizes the need to strengthen early diagnostic pathways and ensure timely multidisciplinary management to mitigate progression in women aged ≤ 40 years.