Abstract PS1-04-08: Five-year longitudinal sociodemographic and lifestyle trajectories among Mexican young women with breast cancer in the Joven & Fuerte cohort

Abstract Background: Breast cancer (BC) diagnosis and treatment can significantly disrupt employment, reproductive, and health behaviors, particularly in young women, with lasting implications for quality of life. However, longitudinal data in Latin American populations remain scarce. This study aimed to characterize five-year sociodemographic and lifestyle trajectories among Mexican young women with BC (YWBC). Methods: Females aged ≤40 years diagnosed with stage I–III BC between 2015 and 2020 were enrolled in the Joven IQR: 32–38), 52.9% had education up to high school. At diagnosis, ∼40% were employed full- or part-time. Employment dropped at 6 months (RR = 0.46; 95% CI: 0.41–0.51) and 1 year (RR = 0.54; 95% CI: 0.49–0.60), both p 0.001. Occupational changes, reported by 70% at diagnosis, increased at 2–3 years (RR = 1.15; 95% CI: 1.05-1.26; p = 0.003) and 4–5 years (RR = 1.23; 95% CI: 1.12-1.34; p 0.001). Income reductions affected 67% at diagnosis and persisted, though likelihood declined at 4–5 years (RR = 0.74; 95% CI: 0.62–0.89; p = 0.001), suggesting partial financial recovery. Relationship status was stable: 78% had a partner at diagnosis; 75% stayed with the same partner at 6 months, and 68% at 4–5 years. Compared to this group, being with a different partner at 1 year (RRR = 0.24; 95% CI: 0.10–0.56; p 0.001) or starting a new relationship at 2–3 years after being single (RRR = 0.31; 95% CI: 0.14–0.72; p = 0.006) was less likely. Fertility preferences declined: 39% desired biological children at diagnosis vs. 20% at 4–5 years (RR = 0.40; 95% CI: 0.17-0.95; p = 0.038). Fewer than 10 live births occurred, and most patients (95-99%) reported no attempts to conceive, with no significant change over time. Lifestyle behaviors improved during the study period. Physical inactivity dropped from 57% at diagnosis to 44% at 4–5 years. At follow-up participants were more likely to engage in 150 min/week (RRR = 1.80; 95% CI: 1.14-2.84; p = 0.01) or ≥150 min/week (RRR = 1.64; 95% CI: 1.07-2.51; p = 0.02). Alcohol intake declined: 2% consumed 20 drinks/week at diagnosis; nearly none by 4–5 years (p 0.001). Less than 20 drinks/week intake also dropped at 6 months and 1 year (p 0.001). Smoking (4-7%) and spirituality (87-93%) showed no significant changes over time. Conclusion: Employment and income disruptions were most pronounced during early post-diagnosis, with only partial recovery observed over time. These findings highlight the need for survivorship plans that incorporate financial support and job reintegration opportunities to help YWBC regain occupational stability. Fertility preferences and attempts to conceive declined during follow-up, while relationship status remained largely stable. Encouragingly, physical activity improved during survivorship. Collectively, these results emphasize the importance of longitudinal support strategies that address the socioeconomic, social, and reproductive health needs of YWBC. Citation Format: F. P. Pons-Faudoa, F. Mesa-Chavez, A. Platas, B. F. Vaca-Cartagena, A. S. Ferrigno, A. Fonseca, M. Miaja, M. Cruz-Ramos, J. E. Bargallo-Rocha, P. Cabrera-Galeana, A. Mohar, C. Villarreal-Garza. Five-year longitudinal sociodemographic and lifestyle trajectories among Mexican young women with breast cancer in the Joven 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-04-08.