• Surgery
• Esophageal Cancer

Esophageal Cancer

The Cause of Esophageal Cancer

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 (SCC)	Adenocarcinoma (AC)
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”.
Risk Factors (Causes)	Age Alcohol Consumption Smoking Male sex African American Ethnicity Certain foods Scalding esophagus with hot drinks Other esophageal medical conditions	Age Acid Reflux (Heart Burn) Pre-cancer cells (Barrett’s Esophagus) Male sex Smoking Obesity Caucasian Ethnicity

Severity of Esophageal Cancer (Grading and Staging)

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.

Staging Esophageal Cancer

The stage of esophageal cancer describes how the disease has spread and relies on the “TNM” system which stands for “Tumour, Nodes, Metastases”.

1. T = Tumour: The cancer size and how deep into the esophagus or beyond it has spread
2. N = Nodes: The number and location of lymph glands that the cancer has spread to
3. M = Metastases: Whether or not the cancer has traveled to locations outside of the esophagus

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

Imaging and Investigations in Esophageal Cancer

Some of the common tests a physician may order to investigate and stage esophageal cancer are described below.

• Computed Tomography (CT) – This imaging method uses elliptical Xrays to construct a two dimensional image of the chest and abdomen that can be viewed from different angles.
• Positron Emission Tomography (PET) Scan – The patient is injected with sugar molecules that have a tracer attached to them. Cells that are growing or multiplying rapidly (for example cancer cells) take up the sugar the most and are seen on imaging. It is most useful for looking at structures around the esophagus.
• Barium Swallow – This test involves swallowing barium and then having images taken of the esophagus to help visualize any cancer masses.
• Upper Endoscopy – In this study a camera enters the esophagus through the mouth to look at the lining of the esophagus. A variety of tools can be used with the camera to sample (biopsy) the cancer. The camera can also use ultrasound to visualize structures around the esophagus.

Surgical Treatment of Esophageal Cancer

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.

• Endoscopic Mucosal Treatment – for a select few Stage I cancers it is possible to remove part of the lining of the esophagus leaving the remaining passage intact. This is only an option for specific types of Stage I cancer. Your thoracic surgeon can provide additional information.
• Esophagectomy – this is the most common operation and involves removal of all or part of the esophagus. In some cases part of the stomach is also removed. Lymph glands are removed from around the esophagus as well. This operation is often coupled with a reconstructive surgery to replace the esophagus.
• Palliative Surgery – the goal of palliative surgery is to relieve pain and suffering and improve quality of life. This can involve a bypass surgery around the esophageal tumour, an esophagectomy, or placement of a feeding tube as examples.

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.
Equivalent Results*	Major Post-operative Complications Ability to sample/remove lymph glands
Inadequate literature to compare	5 yr survival rates Recurrence of esophageal cancer Operative mortality (death)
Benefits	Decreased post-operative pain Possibly Decreased respiratory complications Possibly increased quality of life in short term follow-up after surgery	May be used for more advanced disease or larger tumours
Limitations	Longer operation May not be possible for larger tumours Occasionally the operation must be converted to an open operation to address unexpected findings or complications	Increased trauma to the skin/soft tissues due to large surgical incisions Longer healing time and increased postoperative pain
*Equivalent outcomes are based on single randomized control trial (TIME trial) referenced below.

 

Additional Therapy

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.