| Background:Lung cancer is one of the most common malignant disease,The incidence rate and the mortality of lung cancer rank first among all malignant disease.Small cell lung cancer(SCLC)has a high degree of malignancy and is prone to recurrence and metastasis.Combined small cell lung cancer(C-SCLC)is a subtype of small cell lung cancer,which is composed of small cell lung cancer components and non-small cell lung cancer components.With the improvement of contemporary methods of diagnosis and treatment,the diagnosis rate of C-SCLC has been continuously improved.At present,the research on combined small cell lung cancer is in the exploration stage.It is not clear about the pathogenesis,clinical biological characteristics,Prognostic factors,the connection and difference of combined small cell lung cancer compared with classic small cell lung cancer.At present,there is no large sample to analyze and guide optimal treatment decisions.Objective:The purpose of this study is to analyze the clinical features and prognosis of combined small cell lung cancer and to provide further investigation for research and clinical practice in the future.Methods:We identified 1329 patients with combined small cell lung cancer,the 80,318 patients with small cell lung cancer,and 359,387 patients with non-small cell lung cancer between 1973 and 2015 from SEER Database in this study.The differences of distribution between patients with combined small cell lung cancer and small cell lung cancer were analyzed.The chi-square test was used to compare the differences.The survival curve was drawn by Kaplan-Meier method.The multivariate Cox regression model was used to abtain Survi'val estimates.In an exploratory analysis,we used propensity-score matching(PSM)to compare outcomes between different subgroups of histology.All the statistical methods are performed using the statistical software SAS9.3.Results:The age of onset of C-SCLC patients is mostly under 70 years old(63.4%),male patients are predominant(56.8%),married patients are predominant(55.9%),poorly differentiated and undifferentiated accounted for the majority(52.9%).extensive-stage(stages ? and IV)accounted for the majority(79.1%),and most of them received surgery(51.7%)or chemotherapy(69.9%).The histological grade of C-SCLC tumors is more malignant,the age of patients is more aging,and the stage of initial diagnosis is earlier than SCLC compared with SCLC.More C-SCLC patients are treated with surgery.With the increase of the diagnosis year,the incidence of C-SCLC patients gradually increased.Multivariate Cox regression analysis demonstrated that patients who did not receive radiotherapy treatment carried a 1.19-fold increased risk of all-cause mortality compared with the patients who receive radiotherapy treatment(CSS:HR=1.19?95%CI:1.5-1.34;P<0.001).patients who did not receive chemotherapy treatment carried a 1.8-fold increased risk of all-cause mortality compared with the patients who receive chemotherapy treatment(CSS:HR=1.8,95%CI:1.57-2.06;P<0.001).The patients with stage ?,?,and IV carried a 1.7-fold,2.66-fold and 5.42-fold increased risk of all-cause mortality compared with the stage I patients respectively.The median survival time of non small cell lung cancer,combined small cell lung cancer and small cell lung caner was 12.0 months vs.11.0 months vs.9.0 months.Cancer specific survival(CSS)in patients with combined small cell lung cancer was were medium between small cells and non-small cell lung cancer(P<0.001).Conclusion:Combined small lung caner has unique clinical,pathological,and prognostic characteristics.With the increase of the diagnosis year,the incidence of C-SCLC patients increased gradually.Age,Tumor stage,surgery,chemotherapy status,are radiotherapy status independent predictors of prognosis in patients with combained small lung caner.Tumor-specific overall survival in patients with combined small cell lung cancer was were between of small cells and non-small cell lung cancer(P<0.001). |
PDF Full Text Request