Keywords:
Gastrointestinal tract, Lymph nodes, Oncology, CT, PET-CT, Ultrasound, Staging, Structured reporting, Cancer, Metastases, Neoplasia
Authors:
J. G. Santos1, C. A. Baraças2, L. H. C. B. Samouco1, S. L. Rodrigues1, N. Costa1, L. F. P. Gonçalves3, M. Gouvêa1; 1PORTO/PT, 2Pedrouços - Maia/PT, 3BRAGA, BR/PT
DOI:
10.26044/esti2019/P-0021
Background
Esophageal carcinoma (EC) is the eight most common cancer and the sixth most common cause of cancer-related deaths worldwide. Despite improvements in diagnosis and treatments of EC,
overall 5-year survival rate is still very low (–40%)
Lymph node status has been recognized as one of the most important independent factor that influences the prognosis of EC,
especially the number or ratio of involved nodes - an increasing number of metastatic lymph nodes is associated with a poorer prognosis.
Therefore,
lymphadenectomy’s technique has been recognized as a factor that influences the outcome of surgical treatment for EC.
The lymphatic drainage system of the esophagus is very wide,
including cervical,
mediastinal and celiac node - Fig. 1 and Fig. 2.
Lymph node metastasis spreading may vary with the location of the primary tumor,
the histological type and invasion depth.
There are three pathways for lymph node metastasis in EC.
One is spreading longitudinally along the submucosal lymphatic networks to regional and non-regional lymph nodes; another passes transversely through the muscularis propria to regional lymph nodes; and the last penetrates perpendicularly through the muscularis mucosa to the thoracic duct and the venous system.
Lymphatic routes communicating with periesophageal lymph nodes generally originate from the intermuscular area of the muscularis propria and connections between the submucosal and intermuscular areas do not exist.
Thus,
once the primary tumor infiltrates the submucosa of the esophagus,
the lymph node metastasis might apparently increase.
8th edition American Joint Committee on Cancer (AJCC) Cancer Staging TNM categories are judged clinically (cTNM) based on imaging studies,
with minimal histologic information.
EUS,
CT,
and fluorodeoxyglucose positron emission tomography (FDG-PET) afford regional lymph node imaging and are the principal non-invasive modalities for cN determination - Fig. 3.