According to the study data[1, 2], there were 4.57 million new cases of lung cancer worldwide, accounting for 11.4% of the cancer incidence, ranking second. The number of lung cancer deaths worldwide is 1.8 million, accounting for 18% of cancer deaths, ranking first. China has 820,000 new cases of lung cancer, accounting for 17.9 percent of the cancer incidence, ranking first. China has 710,000 lung cancer deaths, accounting for 23.8 percent of cancer deaths, ranking first. The increasing incidence and mortality of lung cancer have attracted the attention of global scholars[3, 4].
For patients with lung cancer, chemotherapy is still the most important treatment strategy[5, 6]. However, chemotherapy can bring a series of symptoms to patients, such as nausea, vomiting, loss of appetite, hair loss, fatigue, cough, shortness of breath, itchy skin, constipation, pain, etc[7–10]. These symptoms will not only cause patients to experience serious physical and psychological adverse experiences, affect their quality of life, but also bring economic and spiritual burdens to their families[11, 12]. However, these symptoms are not the single existence, often multiple symptoms appear at the same time and affect each other, showing the phenomenon of symptom cluster[13, 14]. The symptom cluster was proposed in 2002 by American scholar Dodd[15] et al, which initially refers to the simultaneous occurrence of three or more interrelated symptoms, and was later redefined by Kim[16] et al. It refers to the simultaneous occurrence of two or more interrelated symptoms, which are synergistic and mutually reinforcing, and have a far greater impact than a single symptom. The symptom cluster affects patients' prognosis, quality of life, and functional status, leading to serious physiological, psychological, and economic burdens, and even delay or discontinue treatment[17, 18]. Patients with lung cancer undergoing chemotherapy have a variety of symptom clusters[19, 20]. Different studies have slightly different classifications of symptom clusters, most studies mainly focus on fatigue related symptom clusters, emotional and psychological symptom clusters, respiratory symptom clusters, digestive system symptom clusters, etc[21–23]. The core symptom cluster refers to the cluster of symptoms with a high incidence, stable existence, and the greatest impact on a patient's quality of life among many symptom clusters[24]. At present, most studies have jointly pointed out that fatigue related symptom clusters in patients with lung cancer undergoing chemotherapy have the highest frequency, earliest occurrence, and heaviest degree, and play a core role[25, 26]. In the previous prospective longitudinal study of our research group, symptom clusters of patients with lung cancer undergoing chemotherapy were investigated at the time of diagnosis, 1 month after diagnosis, and 3 months after diagnosis. The results showed that: Although the composition of symptom clusters varies with time, the incidence of the fatigue-related symptom cluster was high and stable during follow-up, and its severity directly affected other symptom clusters, which was the core symptom cluster of patients with lung cancer undergoing chemotherapy[27]. Fatigue, pain, sleep disturbance, and other symptoms often co-exist in the form of the "symptom cluster" in the treatment period of patients with lung cancer undergoing chemotherapy[28, 29]. Therefore, the fatigue-pain-sleep disturbance symptom cluster was defined as the core symptom cluster of patients with lung cancer undergoing chemotherapy.
Symptom Management Theory (SMT) consists of three interrelated dimensions: symptom experience, symptom management strategy, and management effect[30]. Symptom experience refers to the patient's perception of symptoms, assessment of symptoms, and response to symptoms. Symptom management strategies include when to intervene, where to intervene, who to intervene, and what to intervene specifically. The evaluation indexes of management effect mainly include symptom state, self-management ability, quality of life, psychological state, and so on. At the same time, STM emphasizes the influence of humans, the environment, and health. The management of the core symptom cluster of patients with lung cancer undergoing chemotherapy requires the simultaneous management of fatigue, pain, and sleep disturbance. The evidence on the management of fatigue, pain, and sleep disturbance is extensive, but it is fragmented, and there are many difficulties in the Implementation link[31–35]. Therefore, summarizing the best evidence for the management of the core symptom cluster in patients with lung cancer chemotherapy is the first step in symptom management. However, whether the evidence is directly applicable to complex clinical settings and the importance of the evidence remains to be investigated. Therefore, based on the best evidence of the core symptom cluster management of patients with lung cancer undergoing chemotherapy summarized by our research group in the previous stage, this study intends to construct the core symptom cluster management program for patients with lung cancer undergoing chemotherapy (CSCMP) through Delphi technology under the guidance of SMT, to provide the basis for medical staff and patients to manage the core symptom cluster.