Development and internal validation of a prognostic model of metachronous dual primary lung cancer based on SEER database

Abstract:

Objective: To explore independent prognostic factors of metachronous dual primary lung cancer（mDPLC） by using retrospective analysis，and establish a prognostic nomogram model. Methods: Clinical information of mDPLC patients was collected from Surveillance，Epidemiology，and End Results（SEER） database. The dataset was divided into training and validation sets for modeling and validation. Univariate and multivariable Cox regression analyses were used to explore independent prognostic factors of training set，and the survival time of patients was predicted by nomogram. The accuracy and reliability of the prognostic model were evaluated by C-indexes，calibration plots，receiver operating characteristic（ROC） curves，decision curve analyses（DCA） and integrated discrimination improvement（IDI） scores. Results: A total of 610 mDPLC patients were included in the training set，and 260 mDPLC patients were included in the validation set. Cox regression analysis showed that age（59-76：HR=1.453，95%CI=1.007-2.096，P=0.046；≥77：HR=1.953，95%CI=1.303-2.926，P<0.001），gender（female HR=0.669，95%CI=0.529-0.845，P=0.001），pathological type（adenocarcinoma + squamous carcinoma HR=2.251，95%CI=1.583-3.200，P<0.001），TNM staging（Ⅲ：HR=1.611，95%CI=1.126-2.305，P=0.009；Ⅳ：HR=2.443，95%CI=1.713-3.486，P<0.001），lymph node metastasis（HR=1.653，95%CI=1.199-2.280，P=0.002），surgery（once：HR=1.431，95%CI=1.110-1.844，P=0.006；0：HR=1.845，95%CI=1.183-2.878，P=0.007） and chemotherapy（yes + no：HR=0.603，95%CI=0.433-0.842，P=0.003） were independent prognostic factors. The C-index of training set and verification set were 0.711（95%CI=0.696-0.726，P<0.05） and 0.677（95%CI=0.655-0.699，P<0.05），respectively. The AUC values of 3-year survival rate and 5-year survival rate of ROC curve in training set were 0.756（95%CI=0.713-0.800，P<0.05） and 0.785（95%CI=0.732-0.838，P<0.05），respectively，and the AUC values of the 3-year survival rate and 5-year survival rate of the ROC curve in validation set were 0.695（95%CI=0.621-0.769，P<0.05） and 0.711（95%CI=0.618-0.804，P<0.05）. IDI values of 3 and 5 years were 9.0%（P<0.001） and 11.9%（P<0.001） in the training set，and 6.6%（P<0.001） and 7.8%（P<0.001） in the validation set，respectively. The internal validation showed that the predictive effect of the novel prognostic model was accurate and reliable and was better than that of the model based on TNM system. Conclusion: This study has established a prognostic prediction model of mDPLC，and the internal validation has shown good efficiency，which could provide accurate and personalized survival prediction for mDPLC patients.