Objectives <p>This study aims to quantify the extent to which cognitive emotional regulation and social alienation independently and interactively predict the severity of post-traumatic stress disorder symptoms in patients after radical mastectomy for breast cancer. To test whether cognitive emotional regulation strategies mediate the relationship between fear of cancer recurrence and post-traumatic stress disorder, and to determine whether social alienation mediates the impact of fear of cancer recurrence on post-traumatic stress disorder. It is hypothesized that higher maladaptive cognitive emotional regulation and higher social alienation will respectively explain the unique variations in the severity of post-traumatic stress disorder, rather than merely sociodemographic and medical covariates; The higher the level of cognitive emotional regulation, the more obvious the connection between fear of cancer recurrence and post-traumatic stress disorder. Social distancing can partially mediate the pathway of fear of cancer recurrence - post-traumatic stress disorder. Clarifying these modifiable psychosocial pathways will provide a theoretical basis for alleviating post-traumatic stress disorder in postoperative breast cancer survivors.</p> Methods <p>We recruited 256 eligible patients who had undergone breast cancer surgery to participate in the study using a cross-sectional design. The study discussed the interplay among fear of cancer recurrence, social alienation, cognitive emotion regulation, and post-traumatic stress disorder and aimed to develop effective stress intervention strategies for clinical researchers.</p> Results <p>post-traumatic stress disorder was positively connected with anxiety about cancer recurrence, maladaptive cognitive emotion regulation, and social alienation in patients after breast cancer surgery. Furthermore, the connection between fear of cancer recurrence and post-traumatic stress disorder was influenced by individual maladaptive cognitive emotion regulation and social alienation.</p> Conclusion <p>The fear of cancer recurrence can lead to an increase in post-traumatic stress disorder among breast cancer patients after surgery. This increase is influenced by the adaptability of cognitive emotion regulation and social alienation. Hence, Efforts should be made to prevent negative cognitive emotion regulation. Additionally, patients should be encouraged and supported to enhance their confidence in social interactions and reduce social alienation. These measures aim to alleviate the symptoms of post-traumatic stress disorder.</p> Clinical trial number <p>Not applicable</p>