The esophagus is a muscular tube located in the chest that allows the passage of food from the mouth to the stomach. Disease of the esophagus causes changes to the esophageal lining which can be benign (not cancer), pre-cancerous or cancer.
Table 1: Types of Esophageal Disease
|Benign (not cancer)||When normal cells grow into abnormal structures in the esophagus this is referred to as a benign growth. It means the cells have not transformed into more dangerous cancer cells but are still growing abnormally.|
|Pre-cancerous||Toxic exposures cause changes in the cells that line the esophagus. These changes are termed pre-cancerous when the cells are damaged and changed but not rapidly multiplying or spreading throughout the body. Pre-cancer cells can become cancer with ongoing toxic exposure.|
|Cancer||When cancer develops in the esophagus, it means that cells have transformed and can multiply and grow rapidly and travel to other parts of the body. Cancer cells are called “malignant” and often arise from pre-cancerous cells.|
Risk factors include exposure to substances such as alcohol or cigarette smoke, the presence of acid reflux (heart burn) from the stomach, and ethnicity since certain races have a higher probability of developing cancer.
There are two main types of esophageal cancer each with a different set of risk factors. The two main types are squamous cell carcinoma (SCC) and adenocarcinoma (AC). Other types of esophageal cancer exist but are rare. A summary is provided below.
Table 2: Types of Esophageal Cancer
|Squamous Cell Carcinoma|
|Description||Squamous cells are thin flat cells that line the esophagus. When these cells develop into cancer it is usually in the upper part of the esophagus well above the stomach. Squamous Cell Carcinoma comes from pre-cancer changes known as dysplasia.||This type of cancer results from transformation of tall thin glandular cells. When glandular cells develop into cancer it is usually lower down near the stomach. Adenocarcinoma comes from pre-cancer changes due to stomach acid reflux into the esophagus known as “Barrett’s Esophagus”.|
When esophageal cancer is suspected your doctors will order a variety of tests and investigations to understand how extensive the cancer is.
The goal of these investigations is to determine the type and stage of the cancer. Staging is very important since it determines if and how far the disease has spread around the body.
The stage of esophageal cancer describes how the disease has spread and relies on the “TNM” system which stands for “Tumour, Nodes, Metastases”.
There are four stages of esophageal cancer. The staging system is slightly different for cancer type, but the summary table below simplifies the process. More detailed staging also takes into account the grade and location of the cancer and different sub-categories (Stage IIA, IIB, etc.).
Table 3: Staging of Cancer of the Esophagus*
|Stage I||The cancer is confined within the first few layers of the esophagus. This stage may be treated with surgery alone.|
|Stage II||Cancer may invade to the edge of the esophagus but not beyond and there may be spread to lymph glands. This stage is usually treated with surgery. Sometimes chemotherapy or radiation is required before surgery (called neoadjuvant chemotherapy).|
|Stage III||The cancer may invade beyond the esophagus into surrounding structures and have spread to multiple lymph glands. Chemotherapy or chemoradiation therapy is often instituted before surgery.|
|Stage IV||The cancer has spread to distant areas in the body. Disease around the esophagus is generally extensive and advanced. Chemoradiation therapy is the first line treatment. Surgery is used to relieve symptoms and provide comfort to the patient.|
|*Refer to AJCC Cancer Staging Manual, 7th Ed. (2010) for complete TNM staging classification|
Some of the common tests a physician may order to investigate and stage esophageal cancer are described below.
There are two roles of Thoracic Surgeons in the treatment of esophageal cancer: they can either surgically remove tumours in an attempt to cure the patient of cancer, or they can operate to relieve patient discomfort without curing the disease (called palliative surgery). The following are some of the types of surgical procedures used to treat esophageal cancer.
Esophagectomy is the most common procedure and there are multiple surgical methods available. The options can be divided into two categories: Open Esophagectomy and Minimally Invasive Esophagectomy (MIE).
|Minimally Invasive Esophagectomy (MIE)||Open Lobectomy|
|Description||Surgery that attempts to minimize surgical incisions (cuts) and tissue damage. MIE includes several approaches, most of which use multiple small access ports on the chest to put surgical tools into the patient. Cameras are used to visualize parts of the operation.||A classic surgical approach that opens the chest/abdomen usually with two separate surgical incisions. Different incision locations are possible. This method allows the surgeon to operate with a clear field of vision to the inside of the chest and abdomen.|
|Major Post-operative Complications
Ability to sample/remove lymph glands
|5 yr survival rates
Recurrence of esophageal cancer
Operative mortality (death)
|*Equivalent outcomes are based on single randomized control trial (TIME trial) referenced below.|
Many patients require additional treatment based on the tumour stage. Patients with stage I esophageal cancer usually do not need any additional therapy beyond an operation. Patients with Stage II or higher esophageal cancer are candidates for tri-modality therapy: Chemotherapy + radiation + surgery. Generally speaking, higher Stages of esophageal cancer usually require a more complex treatment course.
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