Tumor location affects the outcome of radiation therapy for esophageal squamous cell carcinoma: A Retrospective Study, Systematic Review, and Meta-analysis

Purpose We aimed to explore the relationship between tumor location and survival in patients with esophageal squamous cell carcinoma(ESCC) undergoing definitive radiotherapy(dRT). Methods We implemented a retrospective analysis (objective remission rates, failure patterns, and survival) of ESCC patients at two participating institutes using Fisher’s exact test, Log-rank testing, and Cox models, respectively. A systematic review and meta-analysis were also performed for patients with ESCC treated with dRT. Results Kaplan-Meier analyses for 732 cases revealed significant differences in the local recurrence-free survival (LRFS), progression-free survival, and Overall survival (OS) based on the tumor location. The poor response rates were 44.5% for the cervical/upper thoracic group, 58.9% for the middle thoracic group, and 62.8% for the lower thoracic group (p < 0.001), respectively. Multivariate analyses showed that the hazard ratio (HR) for the local failure of the middle thoracic group was 1.684, and the lower thoracic group was 2.076 compared with the cervical /upper thoracic group (HR, 1). The tumor location was also an independent prognostic factor for LRFS and OS. Meta-analysis was made from the 12 studies, which included 5554 patients. The results showed that the prognosis and response to the middle and lower thoracic ESCC were significantly worse than those in the cervical/upper thoracic region. Conclusion This retrospective study and meta-analysis confirmed that tumor location is an independent prognostic factor in ESCC patients receiving dRT. The tumors exhibited heterogeneous responses that need to be verified by a large-scale prospective study.