The risk and prognosis of secondary primary malignancy in lung cancer: a population-based study

Aim: To assess and predict risk and prognosis of lung cancer (LC) patients with second primary malignancy (SPM). Methods: LC patients diagnosed from 1992 to 2016 were obtained through the Surveillance, Epidemiology, and End Results database. Standardized incidence ratios were calculated to evaluate SPM risk. Cox regression and competing risk models were applied to assess the factors associated with overall survival, SPM development and LC-specific survival. Nomograms were built to predict SPM probability and overall survival. Results & conclusion: LC patients remain at higher risk of SPM even though the incidence declines. Patients with SPM have a better prognosis than patients without SPM. The consistency indexes for nomograms of SPM probability and overall survival are 0.605 (95% CI: 0.598-0.611) and 0.644 (95% CI: 0.638-0.650), respectively. Lay abstract One of the noteworthy complications in cancer survivors is the development of a second primary malignancy (SPM). This study included lung cancer (LC) patients diagnosed from 1992 to 2016 obtained through the Surveillance, Epidemiology, and End Results database. The authors found that the incidence of SPM in LC has declined. LC patients have a higher risk of a subsequent cancer compared with the general population, especially with regard to digestive, respiratory and urinary system cancers. In this sample, the authors also found that the prognosis of LC patients with SPM is better than that of those without SPM. Finally, this study evaluated the factors influencing the prognosis of SPM patients.