An Overview of Esophageal Cancer Staging

After a diagnosis of esophageal cancer, doctors focus on determining the cancer’s stage and grade. The esophageal cancer staging and grading process can help your doctor make treatment decisions and estimate your chance of recovery (prognosis).

This article will cover the esophageal cancer staging process, how esophageal cancers are staged and graded, how the type of cancer impacts the staging, and some frequently asked questions about esophageal cancer staging. 

Purpose of Cancer Staging

Esophageal cancer is a growth that starts in the esophagus, the tube that leads from your throat to your stomach through which food and liquids travel. A cancerous tumor in the esophagus will grow uncontrollably and can start spreading to other parts of the body. 

If cancer is discovered early, it is easier to treat and cure. After cancer has grown and spread, it is more challenging to treat and more likely to be deadly. 

When doctors first diagnose a cancerous tumor of any kind, they assess how much it has grown, how far it has spread in the body, and how abnormal, or wild, the cancerous cells in the tumor look.

This process is called staging. Cancer stages are determined by the size and locations of the esophageal tumor and some specific characteristics of the type of cancer. They go from stage 0 (often called precancer) to stage 4, the most advanced stage.

Cancer grading is determined by how abnormal, or wild, the cells in the cancer look. The grades go from grade 1 (mostly normal) to grade 4 (highly abnormal).

Doctors use the staging information to compare treatment options and patient outcomes. They’re also important in determining your eligibility for cancer treatment clinical trials.

How Physicians Determine Esophageal Cancer Stages

Cancers are staged based on information gathered through testing. These tests can include blood tests, biopsies (removing a sample tissue for analysis in a lab), and imaging studies like a computed tomography (CT) scan, positron-emission tomography (PET) scan, magnetic resonance imaging (MRI), or ultrasound.

Examining how far cancer has spread is an important part of diagnosis and staging. One of the more important tests for staging esophageal cancer is the endoscopic ultrasound, also known as endosonography. This test uses a lighted tube inserted through the mouth to examine and take samples from the esophagus.

The tube has a tip that the doctor can use to do an ultrasound of the area. In an ultrasound, high-energy sound waves are sent into the tissue, and the computer analyzes how they bounce back to create a picture of the area. 

A thoracoscopy is another procedure doctors may request to get samples of the area or nearby organs and lymph nodes. In this type of endoscopic surgery, a small incision is made between the ribs to insert a tube with a camera, light, and tools to take samples of the esophagus, lungs, and lymph nodes in the chest.

Laparoscopic surgery, a minimally invasive procedure, might also be used to take samples. In a laparoscopy, the surgeon will insert instruments through small incisions made in the side of your abdomen.

The TNM Grading and Staging System

Once the surgeons take samples of the tumors, they’re analyzed by a medical specialist called a pathologist, who studies what cancer looks like under the microscope. This doctor takes pieces of the tumor and shaves them thin, coloring them with special dyes to highlight structures within the cells. 

By comparing the cancer cells to the normal cells around them, the pathologist determines cancer’s grade. The higher the grade, the more abnormal the cells look and the quicker they’re growing.

This information about cancer’s grade and other test results are used to determine cancer’s stage. Esophageal cancer is staged according to the seventh edition of the American Joint Committee on Cancer’s "AJCC Staging Manual," called the TNM staging system.

The TNM system has three parts. Each of these letters is scored from 0 to 4, depending on how severe the cancer is. An X means that doctors couldn't measure that characteristic. A 0 means the cancer isn’t present, and a 4 generally indicates extensive spreading. 

• T stands for tumor: This number indicates how large the tumor is and how much it has grown into the esophageal wall and beyond. T1 tumors have invaded the first layers inside the esophagus, while T4 tumors have spread to other organs and tissues that can't be removed.
• N stands for nodes: This number indicates if cancer has spread to nearby lymph nodes. N0 cancers have not spread to lymph nodes, while N3 cancers are found in more than seven lymph nodes.
• M stands for metastasis: This number indicates if cancer has spread to other organs. M0 means cancer hasn't left the area it originated in, while M1 means it has spread to distant organs.

The doctors first determine cancer's stage based on the TNM numbers, then they add in the grade, the type of cancer, and its location in the upper, middle, or lower third of the esophagus. The higher the stage, the more advanced cancer.

• Stage 1 esophageal cancers are still located close to the inner layer of the esophagus where they developed.
  
• Stage 2 esophageal cancers have spread deeper through the esophageal layers than stage 1 cancers and may have spread to lymph nodes.
• Stage 3 esophageal cancers have spread to nearby lymph nodes and potentially other nearby tissues and local organs. 
• Stage 4 esophageal cancers have spread widely to further organs and tissues around the body.
  

Adenocarcinoma vs. Squamous Cell Carcinoma Staging

There are some variations in the stages between the two types of esophageal cancers: adenocarcinoma and squamous cell carcinoma. Both of these cancers start in the inner lining of the esophagus.

Adenocarcinomas are cancers that come from normal cells that make up our glands (structures that produce and release substances). In the lining of the esophagus, there are many glands that produce mucus to keep our digestive tract moist. When cells of these glands in the esophagus start growing out of control and spreading, they become esophageal cancer.

Esophageal squamous cell carcinoma (SCC) is a cancer that starts in the inner lining of the esophagus. The cells that make up the esophageal lining (and many other organs, including the skin) are thin, flat cells called squamous cells.

The stages for SCC and adenocarcinomas vary somewhat depending on your TNM scores and grade. One important characteristic for staging an esophageal squamous cell carcinoma is the location of the tumor. Cancers that develop in the middle or upper esophagus are given a more advanced stage than those that develop in the lower esophagus with the same characteristics.

If you're confused about your cancer's staging, ask your doctor to explain why a stage was chosen. These staging criteria have changed over time.

Resectable vs. Unresectable Esophageal Cancer

One of the important factors that doctors also include when staging esophageal cancers is the chance a surgeon can remove it. 

The term doctors use for this procedure of removing a tumor is "resection of the tumor." If a tumor is resectable, surgeons will be able to remove it from the esophagus. If it’s unresectable, doctors will not be able to successfully remove it with surgery.

Cancers that fall into stages 0, 1, or 2 are able to be removed by surgery. They are likely or potentially resectable. The patient also needs to be healthy enough to undergo surgery for their tumor to be classified as resectable.

Unresectable cancers have typically grown into essential nearby structures, like the airway, aorta, or spine. Unresectable tumors are harder to treat and have a worse prognosis, as surgery to remove the original tumor is no longer a treatment option. 

Summary 

Cancer stages indicate how advanced a cancer is. They help your doctor determine how best to treat you and what your prognosis is. How your cancer is staged may also determine your eligibility for clinical trials of promising treatments not yet on the market.

Your doctors will perform blood tests, remove and test tumor samples, and have you undergo imaging studies to determine your cancer’s stage and grade.

Esophageal cancer stages are determined by how far the cancer has spread through the layers of the esophagus, into nearby lymph nodes and tissues, and to distant locations in the body like the lungs and liver. 

A Word From Verywell

Being diagnosed with cancer of any kind can be a traumatic experience. Having a better understanding of some of the terminology and why these steps are important in the cancer diagnosis process can help you move forward with your treatment with less fear of the unknown. 

Be sure to ask your doctor any questions about your cancer's staging and what it means.