The results of this study showed that marital status is an independent prognostic factor for patients with small cell lung cancer. SCLC patients in Single group and SDW group had poor prognosis and a higher risk of death. Therefore, the inharmonious marital state is one of the risk factors for poor prognosis of small cell lung cancer. Without the companion, it may easily lead to the change of patients' mood, affect their quality of life, change their role function, and cause serious adverse effects on their psychological state[16, 17] Studies have found that mental state can affect the progress of tumor, aggravate the clinical symptoms of patients, and then affect the clinical prognosis[18]. Positive emotions have a buffering effect on stress, can alleviate the psychological burden, stimulate patients to take positive behaviors, and significantly improve the psychological state and prognosis of cancer patients[19]. However, negative emotions may induce changes in the respiratory system and cardiovascular system, which may lead to poor prognosis[20].
The researchers conducted a large epidemiological survey and analyzed data from 1,260,898 patients with various types of tumors, such as prostate cancer, breast cancer, lymphoma, colorectal cancer, pancreatic cancer, ovarian cancer, esophageal cancer, lung cancer, head and neck tumors, etc[21, 22]. The results showed that after correction for all confounding factors, married cancer patients had a lower risk of death from cancer. Researchers have analyzed that cancer patients in happy families were more likely to receive health checkups recommended by their family members, so that they can be diagnosed and treated early in the disease[23]. At the same time, after being diagnosed, these patients are more willing to strictly follow the treatment plan and conduct the follow up supervision regularly. The results show social support is important for cancer patients[24].
Cancer has an impact on both physiology and psychology of patients. For example, the clinical symptoms of the disease will bring physical pain to patients, and the fear of disease recurrence and death will make patients suffer from psychological loneliness and depression[25]. Social support is considered to be that individuals receive support from the outside world, including material and spiritual guarantees, which directly promote the physical and mental health of individuals Study showed that social support can inhibit the progress of cancer[26]. Compared with the control group, the survival rate of the group participating in social support was significantly improved. Marriage is a form of social support. Social support in marriage mainly comes from the spouse. The patient's spouse can provide effective emotional comfort and social environment support in time to reduce the psychological stress of the patient[27]. Therefore, single or SDW patients with SCLC should be provided with active psychological counseling. The doctors should answer patient questions patiently, communicate in a timely manner and give psychological intervention to reduce the negative emotions of patients, so as to improve their quality of life and prolong their survival time. It is also suggested for the medical staff to give patients more humane care and emotional support while treating tumors, this will reduce their psychological pain, improve their internal control, and then effectively improve their psychological state[28].
The SEER database provides us the opportunity to perform large, population-based studies. However, there are several limitations in our study. An obvious limitation is that this is a retrospective study that has a greater probability of bias than prospective studies. In addition to demographic and clinical factors, there is a relative lack of control variables. For example, the database cannot provide important confounding variables such as smoking history, patient complications, and other treatment options. Secondly, the marital status recorded in the SEER database is only the marital status at the time of diagnosis. As for whether the patient's subsequent marital status has changed, no follow-up visits and records have been performed, so the impact of this change on the study cannot be estimated. Thirdly, the SEER database does not incorporate data on the life quality of married patients, such as marital satisfaction or financial status.
Despite of these potential limitations, this is the first study investigating the effect of marital status on prognosis of SCLC by big data. It suggests that doctors should pay more attention to unmarried or SDW patients. This will improve the mental health problems of such patients caused by the lack of companion, thus achieve better clinical treatment measures and improve the long-term prognosis.