["Psycho-Oncology, Volume 35, Issue 5, May 2026. ", "\nABSTRACT\n\nPurpose\nBreast cancer patients often experience significant psychological distress. This study examined distress trajectories from diagnosis to 6 months post‐treatment and explored differences across demographic, medical, and psychosocial subgroups.\n\n\nMethods\nIn this prospective cohort study, 528 patients with breast cancer were recruited between 1 December 2023 and 31 December 2024. Assessments were conducted at baseline (at diagnosis, T0), after the first treatment (T1), mid‐treatment (T2), at treatment completion (T3), and at three (T4) and six months (T5) post‐treatment. Growth mixture modeling (GMM) was used to identify distinct trajectories of psychological distress. Multinomial logistic regression analysis was performed to examine associations between patient‐related factors and trajectory membership.\n\n\nResults\nThree psychological distress trajectories were identified: a high‐distress remission group (17.05%), a moderate‐stable distress group (11.93%), and a low‐fluctuating distress group (71.02%). Multivariable analyses showed that higher educational attainment, breast‐conserving surgery, early disease stage, partial self‐management ability, and strong social support were associated with membership in the moderate‐stable or low‐fluctuating groups (p < 0.05). Employment, health insurance coverage, avoidant medical coping style, and higher baseline anxiety and depression scores were concurrently associated with membership in the high‐distress remission group (p < 0.05).\n\n\nConclusions\nAlthough psychological distress generally decreased over time, 71.02% of patients followed a low‐fluctuating trajectory, 11.93% maintained moderate distress with potential risk of persistence, and 17.05% showed high initial distress that remitted substantially within 6 months. Continuous monitoring and early psychosocial support are recommended, particularly for patients with moderate‐ or high‐risk trajectories.\n\n"]