In the NCCN guideline for esophageal and EGJ cancers (version 3, 2015), PNI is recommended as a high-risk feature to guide the postoperative treatment of lower-esophagus and EGJ adenocarcinoma patients.
We also evaluated the relationship of PNI with the well known and established prognostic criteria, including T, N stage and histological grade, which constitute the basis for the AJCC TNM classification of esophageal and EGJ cancer .
This meta-analysis, to our knowledge, is the first study to systematically evaluate the prognostic significance of PNI in esophageal and EGJ carcinoma.
In conclusion, PNI is an independent and adverse prognostic indicator which implies aggressive and metastatic behaviors of tumor cells in esophageal and EGJ carcinoma patients treated with surgery.
In a comparison study of the relationship among the distal end of esophageal longitudinal vessels, the proximal end of gastric mucosal folds, and the most distal end of deep esophageal glands and ducts, Sato et al (17) systematically investigated the entire EGJ in 87 consecutive resection specimens from patients with esophageal squamous cell carcinoma.
In summary, the results of the studies from Japan suggest that the distal end of esophageal longitudinal veins may be more accurate than the proximal end of gastric mucosal folds as the true mucosal EGJ landmark.
In a healthy person without reflux esophagitis, the macroscopic mucosal EGJ is at the same level as the microscopic SCJ (Figures 3 and 4).
In summary, the SCJ may be displaced proximally and move away from the mucosal EGJ in American patients and cannot be used as a gold standard for the true mucosal EGJ to guide the endoscopic study in a general practice setting.
At present, in a small biopsy specimen from the EGJ region, distinction between the proximal stomach and the distal esophagus is heavily dependent upon the endoscopist's impression of the precise location of a biopsy site.
19,27,28) Therefore, these histologic landmarks are currently the gold standard of the esophagus and used to histologically define the mucosal EGJ.
At present, the best histologic markers of the mucosal EGJ are the distal ends of (1) squamous epithelium, (2) deep esophageal glands and ducts, and (3) multilayered epithelium.