This article was last reviewed and updated on November 20, 2019
by Jason Wasserman, MD PhD FRCPC
The esophagus is a long hollow tube that starts at the back of your throat and ends at the top of your stomach. Swallowed food travels down the esophagus into the stomach.
The esophagus is made up of six layers of tissue:
What is squamous cell carcinoma?
Squamous cell carcinoma is associated with both long term alcohol use and smoking although a variety of injuries and chemicals can also cause squamous cell carcinoma in the esophagus.
Symptoms of squamous cell carcinoma in the esophagus include difficultly or pain when swallowing food. The symptoms are worse initially with solids but progress to both solids and liquids.
The diagnosis of squamous cell carcinoma is usually made after a small sample of tissue is removed in a procedure called a biopsy and the tumour is later removed in a resection specimen such as an esophagectomy.
Pathologists divide the grade into three categories based on how the cancer cells look when examined under the microscope.
Why is this important? Grade is important because poorly differentiated tumours are more likely to spread to other parts of the body and to re-grow after treatment.
The esophagus is a long tube that starts at the back of your throat and ends at the top of the stomach. The normal esophagus is divided into three parts:
In your report, tumour site refers to the part of the esophagus or stomach involved by the tumour. Most squamous cell carcinomas start in the cervical or thoracic part of the esophagus.
This is the size of the tumour. Tumour size will only be described in your report after the entire tumour has been removed. The tumour is usually measured in three dimensions but only the largest dimension is described in your report. For example, if the tumour measures 4.0 cm by 2.0 cm by 1.5 cm, your report will describe the tumour as being 4.0 cm.
The esophagus is a tube and the wall of the tube is made up of six different layers of tissue (see The esophagus above). Squamous cell carcinoma starts in the epithelium on the inner surface of the esophagus. The movement of cancer cells from the epithelium into the tissue below is called invasion.
Tumour extension describes how far the cancer cells have spread from the epithelium into the layers of tissue below.
Your pathology report will describe the tumour extension as follows:
Why is this important? Tumour extension is important because it is used to determine the pathologic tumour stage (see Pathologic stage below). Cancer cells that have spread further into the wall of the esophagus or surrounding organs are more likely to come back after treatment in the area of the original tumour or spread (metastasize) to a distant site such as the lungs.
Nerves are like long wires made up of groups of cells called neurons. Nerves send information (such as temperature, pressure, and pain) between your brain and your body. Perineural invasion means that cancer cells were seen attached to a nerve.
Why is this important? Cancer cells that have attached to a nerve can use the nerve to travel into tissue outside of the original tumour. This increases the risk that the tumour will re-grow in the same area of the body (recurrence) after treatment.
Blood moves around the body through long thin tubes called blood vessels. Another type of fluid called lymph which contains waste and immune cells moves around the body through lymphatic channels.
Cancer cells can use blood vessels and lymphatics to travel away from the tumour to other parts of the body. The movement of cancer cells from the tumour to another part of the body is called metastasis.
Before cancer cells can metastasize, they need to enter a blood vessel or lymphatic. This is called lymphovascular invasion.
Why is this important? Lymphovascular invasion increases the risk that cancer cells will be found in a lymph node or a distant part of the body such as the lungs.
In the esophagus, a margin is any tissue that was cut by the surgeon in order to remove the tumour from your body. The types of margins present will depend on the type of procedure that was performed.
For esophagectomy specimens where an entire segment of esophagus has been removed, the margins will include:
For endoscopic resections where only a small piece of the inside of the esophagus has been removed, the margins will include:
In the esophagus, a margin is considered positive when there are cancer cells at the very edge of the cut tissue.
Why is this important? A positive margin is associated with a higher risk that the tumour will re-grow in the same site after treatment.
Lymph nodes are small immune organs located throughout the body. Cancer cells can travel from the tumour to a lymph node through lymphatic channels located in and around the tumour (see Lymphovascular invasion above). The movement of cancer cells from the tumour to a lymph node is called a metastasis.
Lymph nodes from the neck are sometimes removed at the same time as the main tumour in a procedure called a neck dissection. The lymph nodes removed usually come from different areas of the neck and each area is called a level. The levels in the neck include 1, 2, 3, 4, and 5. Your pathology report will often describe how many lymph nodes were seen in each level sent for examination.
Your pathologist will carefully examine each lymph node for cancer cells. Lymph nodes that contain cancer cells are often called positive while those that do not contain any cancer cells are called negative. Most reports include the total number of lymph nodes examined and the number, if any, that contain cancer cells.
Why is this important? Finding cancer cells in a lymph node is associated with an increased risk that the cancer cells will spread to other parts of the body. The number of lymph nodes with cancer cells is also used to determine the nodal stage (see Pathologic stage below).
If you received treatment (either chemotherapy or radiation therapy) for your cancer prior to the tumour being removed, your pathologist will examine all of the tissue submitted to see how much of the tumour is still alive (viable).
The treatment effect will be reported on a scale of 0 to 3 with 0 being no viable cancer cells (all the cancer cells are dead) and 3 being extensive residual cancer with no apparent regression of the tumour (all or most of the cancer cells are alive).
Lymph nodes with cancer cells will also be examined for treatment effect.
The pathologic stage for squamous cell carcinoma is based on the TNM staging system, an internationally recognized system originally created by the American Joint Committee on Cancer.
This system uses information about the primary tumour (T), lymph nodes (N), and distant metastatic disease (M) to determine the complete pathologic stage (pTNM). Your pathologist will examine the tissue submitted and give each part a number. In general, a higher number means more advanced disease and worse prognosis.
Tumour stage (pT) for squamous cell carcinoma of the esophagus
Squamous cell carcinoma is given a tumour stage between 1 and 4 based on the distance the cancer cells have traveled from the epithelium on the inner surface of the esophagus into the wall of the esophagus.
Nodal stage (pN) for squamous cell carcinoma of the esophagus
Squamous cell carcinoma is given a nodal stage between 0 and 3 based on finding cancer cells in a lymph node and the number of lymph nodes involved.
If no lymph nodes are submitted for pathological examination, the nodal stage cannot be determined and the nodal stage is listed as NX.
Metastatic stage (pM) for squamous cell carcinoma of the esophagus
Squamous cell carcinoma is given a metastatic stage of 0 or 1 based on the presence of cancer cells at a distant site in the body (for example the lungs). The metastatic stage can only be determined if tissue from a distant site is submitted for pathological examination. Because this tissue is rarely present, the metastatic stage cannot be determined and is listed as X.