Second primary malignancy in patients with esophageal adenocarcinoma and squamous cell carcinoma

There have been no studies on implementing effective screening models for esophageal adenocarcinoma and squamous cell carcinoma survivors. We used a proportional subdistribution hazards model to estimate second primary malignancy risks among patients with esophageal adenocarcinoma and squamous cell carcinoma. We validated models using a bootstrap cross-validation method and performed decision curve analysis to evaluate their clinical utility. Age group and SEER historic stage were significantly associated with second primary malignancy risk after diagnosis of esophageal adenocarcinoma and squamous cell carcinoma. Saving positive lymph nodes and distant metastasis were significant factors in the adenocarcinoma group, and marital status, tumor location, and chemotherapy were significant factors in the squamous cell carcinoma group. Calibration plots show good concordance between predicted and actual outcomes except in high-probability areas for the risk of a second primary malignancy in patients with esophageal squamous cell carcinoma. Discrimination performances of the Fine-Gray models were evaluated using c-indices, which were 0.691 and 0.662 for second primary malignancies in patients with esophageal adenocarcinoma and squamous cell carcinoma, respectively. Decision curve analysis yielded a range of threshold probabilities (0.020-0.177 and 0.021-0.133 for patients with esophageal adenocarcinoma and squamous cell carcinoma, respectively) at which the clinical net benefit of the risk model was larger than those of hypothetical all-screening and no-screening scenarios. Our nomograms enable selection of patient populations at high risk for a second primary malignancy and thus will facilitate the design of prevention trials for affected populations.