Clinicopathological Characteristics And Prognosis Of Transformed Lung Cancer

Background:Lung cancer is one of the leading causes of cancer morbidity and mortality.There is a special pathological type in lung cancer called transformed lung cancer,which is a type of non-small cell lung cancer transformed into small cell lung cancer.However,the clinicopathological characteristics of this subtype of lung cancer and the mechanism of transformation are still unclear.There is no uniform standard for the treatment of transformed lung cancer.Objective:The purpose of this study is to analyze the transformation time,clinicopathological features,treatment options,and prognosis of transformed lung cancer.Methods:We used the National Cancer Institute’s Surveillance,Epidemiology and Outcomes Database to select patients with lung cancer from 1988 to 2016.Collected relevant clinical data,including gender,age,year of diagnosis,region,race,marital history,pathological grade,tumor pathological type,tumor staging,treatment method and survival time,retrospectively analyzed Clinicopathological characteristics and prognosis of transformed lung cancer,non-small cell lung cancer and small cell lung cancer.The primary study endpoint was overall survival(OS).The χ2 test was used to compare the clinical case data,the Kaplan-Meier survival curve was drawn,the prognostic factors were analyzed by multivariate COX,and the 1:1 propensity score matching was used to compare the prognosis of transformed lung cancer with non-small cell lung cancer and small cell lung cancer.All statistical analyses were carried out by SAS software(version 9.4;SAS Institute,Cary,NC,USA).P-values less than 0.05 were considered statistically significant.Results:In this study,468,824 patients with lung malignancies were selected from the 1988-2016 SEER database.Among them,non-small cell lung cancer:382,200,small cell lung cancer:85,849,and transitional lung cancer:775.The results showed that compared with non-small cell lung cancer and small cell lung cancer,women with transformed lung cancer had a higher proportion(52.3%),more patients with high and medium differentiation(40.6%),and the highest proportion of patients with early-stage(Ⅰ)(65.2%),The proportion of patients undergoing surgery was the highest(77.5%),while the proportion of patients receiving chemotherapy and radiotherapy was less,with significant statistical differences.There were significant differences in the conversion time between the three groups of 0-24 months,25-60 months,and more than 60 months(The median transformation time for the three groups was 10 months/42 months/90 months,P<0.001).The prolongation of transformation time significantly prolonged the survival time of lung cancer patients(24,57 and 107 months respectively,P<0.001).The median overall survival(mOS)of 775 patients with transformed lung cancer was 66 months,the median time to transformation was 45 months,The median overall survival of non-small cell lung cancer was 11 months,and that of small cell lung cancer was only 9 months.There was a significant difference in survival between the three groups(P<0.001).After the 1:1 propensity score matching(PSM),the risk of death for patients with transformed lung cancer was 26%lower than that of non-small cell lung cancer between 1988 and 2002(HR:0.74,95%CI:0.63-0.88;P<0.001),2003-2016 transformed There is no significant difference in survival time between lung cancer and non-small cell lung cancer,and the survival time of transformed small cell lung cancer and simple small cell lung cancer is similar,with no significant statistical difference(HR:0.97,95%CI:0.87-1.07;P=0.509).Conclusion:Transformed lung cancer has unique clinicopathological characteristics.Patients with transformed lung cancer tend to be younger,have early clinical stages,and have a higher degree of tumor differentiation.Most of them underwent surgical treatment.After the first-generation EGFR-TKI was launched in 2003,the time to transformation of patients with newly diagnosed stage Ⅲ-Ⅳ adenocarcinoma was shorter than before 2003,and the overall median survival time was also shorter than before.The earlier the transformation of lung cancer,the worse its prognosis.The prognosis of transformed lung cancer is better than those of non-small cell lung cancer and small cell lung cancer.After the conversion of non-small cell lung cancer into small cell lung cancer,the clinical characteristics and biological behavior are similar to those of classic small cell lung cancer,and the median overall survival is similar.