Staging: Part Art, Mostly Science
Staging is a standardized way physicians evaluate the extent of tumor(s) in the body and group these findings into categories called “stages” in order to simplify the planning for further diagnosis and treatment. This also aids in the keeping of statistical records, such as the hospital tumor registry. It is important that the patient and family know as much as possible about this process in order to understand discussions as to how advanced the tumor is and what may be the outcome of treatment.
Keep in mind that every major tumor type in the body is staged in a different way.
Step One: Assessing each factor - Size, Location and Reach
“T” refers to “Tumor”. It primarily involves how deeply the tumor has grown into the four layers of the esophagus (from the inside to the outside). T1 indicates that the tumor is only into the first layer, T4 indicates growth into the loose tissue around the outside of the esophagus. (Cis) is a term used for “Carcinoma in situ”, a condition in which the cancer has only involved the epithelium. In the esophagus this is called “high grade dysplasia” in pathology reports.
“N” refers to the spread of tumor to lymph nodes that are quite close to the primary tumor in the esophagus. N0 means that there is no tumor in nearby nodes, while N1 indicates spread to at least one nearby node. (After January 2010, the number of nodes involved is used).
“M” refers to metastases. This term, as used in the esophageal cancer staging definition, means spread to a more distant lymph node or to other body organs. M0 means there is no spread. M1a means spread to lymph nodes fairly close to the esophagus. M1b means spread to far away lymph nodes or other organs such as the liver, lung, pleura, etc. After January 2010 a different system is used.
Step Two: Combining the Factors
- Stage 0 – Tis, with N0 and MO.
- Stage I and Stage IIA involve T1, T2, or T3, with N0 and MO. This means tumor is present in the esophageal wall, but not elsewhere.
- Stage IIB – the tumor has invaded the muscle layer and spread to nearby lymph nodes. It has not invaded the covering layer of the esophagus.
- Stage III – the tumor in the third layer of the esophagus and nearby lymph nodes, or in layer 4 of the esophagus. No distant tumor is present.
- Stage IVA – indicates tumor in a moderately close lymph node, (N1), but not in other nodes or organs, (a TNM category called M1a).
- Stage IVB – indicates tumor in distant lymph nodes or other organs, (a TNM category called M1b).
A major change in how EC is staged took place in January 2010. After that date, all newly discovered EC tumors will be staged in this new way. The following discussion only refers to tumors staged before the year 2010. NCI addresses the new standards for staging.
Note: both squamous carcinoma and adenocarcinoma are staged in exactly the same way in the pre-2010 method, but after January 2010 separate methods are applied.The article entitled “Staging Esophageal Carcinoma in the Second Decade of the 21st Century” By Richard Stienmier, a Medical Doctor, (Pathologist), who has had chemo-radiation followed by an esophagectomy for esophageal adenocarcinoma and has been free of cancer since 2002.