Clinical features and risk of multiple primary malignancies after endoscopic treatment in patients with early esophageal squamous cell carcinoma: a retrospective cohort study.

Background: The incidence of multiple primary malignancies (MPMs) after early esophageal cancer is increasing. This study aimed to explore the clinical features of patients with MPMs and identify independent risk factors for the development of MPMs after endoscopic treatment in early esophageal squamous cell carcinoma (ESCC) patients.

Methods: Patients diagnosed as early ESCC at Beijing Friendship Hospital were retrospectively analyzed. Independent factors affecting MPMs were selected by univariate and multivariate Cox regression analyses.

Results: Among 299 patients with early ESCC, the mean age was 64.22 years; 219 were male (73.24%). Of these, 32 patients (10.70%) developed MPMs during a follow-up period of 120 months; 10 were metachronous and 22 synchronous. Multivariate Cox analysis showed that alcohol drinking ≥5 standard drinks/day [hazard ratio (HR) =4.21, 95% confidence interval (CI): 1.79-9.90, P<0.001], lower location (HR =2.49, 95% CI: 1.18-5.22, P=0.02), submucosal infiltration depth (HR =3.38, 95% CI: 1.31-8.69, P=0.01), and multiple lesions (HR =2.41, 95% CI: 1.15-5.04, P=0.02) were independent risk factors for developing MPMs in patients with early esophageal cancer.

Conclusions: Early ESCC is associated with a high risk of developing MPMs. Monitoring the development of MPMs in patients with early ESCC based on identified risk factors is of great importance.