Lung cancer ranks as the second most prevalent cancer globally, accounting for 11.4% of the total incidence of cancer [1]. In China, lung cancer is the most common malignant tumor and the leading cause of cancer-related death [2]. Lung cancer can be divided into small cell lung cancer and non-small cell lung cancer according to cell type, with non-small cell lung cancer accounting for approximately 85% of diagnoses [3]. Surgical resection is still the main treatment method, particularly for patients with early-stage non-small cell lung cancer, with a 5-year survival rate generally ranging between 70% and 80% [3]. Preoperative lung lesions and tumor compression of surrounding tissues can easily lead to adverse symptoms such as dyspnea and fatigue in lung cancer patients [4,5]. The surgery procedure itself often leads to reduced lung tissue and decreased respiratory muscle mobility, making it difficult for patients to breathe deeply and cough effectively, which can easily aggravate dyspnea, cause postoperative pulmonary complications, and further reducing overall quality of life (QOL) [[6], [7], [8]]. At the same time, due to the fear of surgery and uncertainty about the prognosis of the disease, patients may experience adverse emotions such as anxiety and depression, which is detrimental to their recovery [9,10]. Given the symptom burden of the cancer itself and a range of surgery-related symptoms, it is necessary to actively seek an intervention that can improve the perioperative physical and mental symptoms in lung cancer patients to accelerate recovery.

Mindfulness interventions have received widespread attention in recent years and are gradually expanding into fields such as neuroscience, medicine and psychology, and have been used in clinical settings to help perioperative patients improve their physical and psychological symptoms [11]. As one of the important techniques of mindfulness intervention, mindful breathing training has become a promising method for the rehabilitation of lung cancer surgery patients. It offers a wide range of benefits, including low requirements for patients' physical activity level, making it particularly suitable for perioperative lung cancer patients who often have limited mobility due to surgical incisions and various postoperative catheters [12,13]. In addition, it is cost effective, easy to learn and understand, patients only need a mobile phone or other daily tools to follow the audio guidance to complete the training.

Mindful breathing training emphasizes nonjudgmental awareness of one's moment-to-moment experience and emphasizes focusing attention on breath control [12]. This approach helps to balance the sympathetic and parasympathetic nervous systems, reduces stress levels and inflammatory reactions, and therefore focuses more on both physiological and psychological effects than deep breathing training [12,14,15]. More importantly, patients with lung cancer in the perioperative period are in a state of stress, with accelerated respiratory rate and increased ventilation, and the respiratory training component of mindful intervention can help patients regulate respiratory disorder, improve alveolar ventilation and gas distribution, and reduce respiratory power consumption [16,17]. Previous studies have shown that mindful breathing training can reduce dyspnea [18,19]and improve emotional state [20,21]. As preoperative breathing training can significantly improve patients' tolerance to surgery and subsequent treatment, this study considered implementing the intervention throughout the perioperative period, rather than just after surgery [22].

Notably, the effectiveness of mindful breathing training and similar interventions often hinges on patients' training compliance [23]. Common factors affecting patients' training compliance include poor health care awareness, lack of self-efficacy, lack of support from family members, etc [24]. Diary-based rehabilitation guidance refers to recording patients' daily rehabilitation training through the mindful breathing training diary and evaluation form to achieve evaluation and tracking of training, with the aim of improving patients' rehabilitation outcomes [25]. Studies have shown that diary-based rehabilitation guidance can effectively improve patients' training compliance, thereby improving rehabilitation outcomes [26,27].

Therefore, this study aimed to explore the effects of mindful breathing training combined with diary-based rehabilitation guidance on dyspnea, fatigue, anxiety, depression, training compliance and self-efficacy in lung cancer patients undergoing surgery, in order to provide reference for its application and development in practical clinical settings.