Patterns of metastasis and prognosis of elderly esophageal squamous cell carcinoma patients in stage IVB: a population-based study

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) has been listed among the most common esophageal cancers (ECs). Patients are generally relatively old in terms of their age at diagnosis of ESCC. A retrospective, population-based study appraising 537 elderly ESCC patients who suffered distant metastasis (DM) in stage IVB from 2010 to 2016 was performed. To this end, data pertaining to Surveillance, Epidemiology, and End Results (SEER) were adopted. METHODS: A total of 537 elderly patients with IVB-stage ESCC suffering DM treated from 2010 to 2016 were taken as subjects. Prognosis was determined by using Kaplan-Meier analysis, as well as univariate and multivariate Cox regression. In accordance with sites of metastasis, these patients were classified into five groups: bone-, lung-, brain-, liver-only, and multiple-site (metastases to two or more organs) groups. In order to assess the prognosis, the cancer-specific survival (CSS), median survival time (MST), overall survival (OS), and survival rate (SR) were examined. RESULTS: The lung was found to be the organ most vulnerable to metastasis in the population with single-organ metastasis, and liver, bone and brain followed in descending rank order. Relative to the group only having bone metastasis, the multiple-site group had the lowest CSS (HR: 1.067; 95% CI: 0.767–1.485; P=0.700) and OS (HR: 1.051; 95% CI: 0.759–1.454; P=0.766). The MST (MST: both 2 months in CSS and OS) and SR (6-month SR: 28.2% in CSS, 27.7% in OS; 1-year SR: 7.5% in CSS, 6.7% in OS; 3-year SR: 2.5% in CSS, 1.5% in OS) were also found to be the lowest for the multiple-site group among the total population. These patients benefited from treatment with chemotherapy (C), radiotherapy (R), and surgery (S), as evinced by the prognosis (CSS and OS: P<0.001), in comparisons with untreated patients (N) in the total population. The S or/and R + C resulted in no statistically significant differences to C alone (CSS: P=0.593; OS: P=0.510) in terms of the prognostic results, which indicated that C alone can have almost the same prognostic effect as multimodal therapy. CONCLUSIONS: Population-based research was used to determine patterns of metastasis and survival outcomes of elderly patients with IVB-stage ESCC suffering DM. The worst CSS and OS were found in patients with multiple-site metastasis across all groups. The treatment is an independent prognostic factor affecting prognosis. Chemotherapy plays a vital role in prognosis. Active therapies are beneficial to elderly patients with IVB-stage ESCC suffering DM, particularly chemotherapy.