Diagnosis of Esophageal Cancer

Executive Summary

Different tests are available to esophageal cancer diagnosis development, depending on signs and symptoms, age and health status, types of tumor, and earlier medical tests. Physical examination, imaging tests, and biopsies are the common diagnostic approaches for esophageal cancer diagnosis. The physical examination will include the Barium swallow (esophagram), Upper endoscopy (esophagus-gastro-duodenoscopy), endoscopic ultrasound, and bronchoscopy. A biopsy will consist of tissue sample extraction for cancer diagnosis. Biomarker testing of the tumor will include molecular testing involving PD-L1 and microsatellite instability (MSI) testing and HER2 testing. The imaging tests include Computed tomography (CT) scan, Magnetic Resonance Imaging (MRI), and Positron emission tomography (PET) or PET-CT scan. 

Diagnosis of Esophageal Cancer

Many tests are performed to find or esophageal cancer diagnosis. They also do tests to see if cancer has spread to another part of the body from where it began. If this happens, it is called metastasis. For instance, imaging tests can represent if cancer has spread. Imaging tests show pictures of the body from the inside. Doctors can also do tests to learn which treatments would work best.

A biopsy is the sure short way for the doctor to know if an area of the body has cancer for most types of cancer. In a biopsy, the doctor takes a small tissue sample for testing in a laboratory. The doctor may suggest other tests if a biopsy cannot help diagnose.

The doctor may consider given factors when choosing a diagnostic test:

• Your signs and symptoms
• The age and general health status
• The type of cancer suspected
• The result of earlier medical tests

In addition to a physical examination, the below-mentioned tests may be used to esophageal cancer diagnosis^​1​:

• Barium swallow, also called an esophagram – The patient swallows a liquid containing barium, and then a series of x-rays are taken ^​2​. An x-ray is a method to take a picture of the inside of the body. Barium coats the surface of the esophagus, making a tumor or other unusual changes easier to see on the x-ray. If an area looks abnormal, your doctor may recommend an upper endoscopy and biopsy to determine whether it is cancerous (see below).
• Upper endoscopy, also called esophagus-gastro-duodenoscopy, or EGD- An upper endoscopy allows the doctor to see the esophagus lining ^​3​. A thin, flexible tube with a light and video camera on end, called an endoscope, is passed down the throat and into the esophagus while the patient is sedated. Sedation is giving medication to become more calm, relaxed, or sleepy. If there is an abnormal-looking area, a biopsy will be performed to determine cancer. An endoscopy using an inflatable balloon to stretch the esophagus can help broaden the blocked area so that food can pass through till the treatment starts.
• Endoscopic ultrasound – This procedure is often done simultaneously as the upper endoscopy. During an ultrasound, sound waves show a picture of the esophagus wall and nearby lymph nodes and structures. An endoscopic probe with an attached ultrasound that produces the sound waves is inserted into the esophagus through the mouth during an endoscopic ultrasound. The ultrasound is used to determine if the tumor has grown into the esophagus wall, how deep the tumor has grown, and whether cancer has spread to the lymph nodes or other nearby structures. An ultrasound can also help get a tissue sample from the lymph nodes.
• Bronchoscopy – Like an upper endoscopy, the doctor passes a flexible, thin tube with a light on the end into the mouth or nose, down through the windpipe, and into the breathing passages of the lungs. A bronchoscopy may be performed if a tumor is located in the upper two-thirds of the esophagus to find out if the tumor is growing into the airway. This part of the airway includes the trachea and the area where the windpipe branches out into the lungs, called the bronchial tree.
• Biopsy – Other tests suggest that cancer is present, but only a biopsy can make a definite diagnosis. A biopsy removes a small amount of tissue from the suspicious area for examination. A pathologist then analyzes the sample. 
• Biomarker testing of the tumor – Your doctor may recommend running laboratory tests on a tumor sample to identify specific proteins, genes, and other factors unique to the tumor. This is also called molecular testing of the tumor. Results of these tests can help determine the treatment options.
  • PD-L1 and microsatellite instability (MSI) testing – Testing for PD-L1 and high microsatellite instability (MSI-H) can also be called a mismatch repair deficiency. These tests help doctors determine if a treatment called immunotherapy is an option. The PD-1/PD-L1 pathway is an immune checkpoint. These checkpoints are critical to the immune system’s ability to control the growth of cancer cells. Many cancers use these pathways to escape the immune system. If particular antibodies are given for treatment to block these pathways, the immune system may overcome the suppression by cancer. These antibodies are immune checkpoint inhibitors. Drugs targeting this pathway can be effective against MSI high or MSI-H, or PD-L1 positive esophageal cancers. PD-L1 and MSI testing is common for advanced or stage IV esophageal cancer ^​4​.
  • HER2 testing – Human epidermal growth receptor 2 is a specialized protein found on the surface of cells. Many people are familiar with HER2 when discussing breast cancer. However, doctors are searching for HER2 is also essential in other types of cancer. When cancer has abnormally high levels of HER2, it can drive its growth and spread. These cancers are referred to as HER2-positive. For HER2-positive cancers, some types of targeted therapy can work well to treat these cancers. 
• Computed tomography (CT or CAT) scan – A CT scan takes images of the body inside using x-rays taken from different angles. A computer combines photos into a detailed, 3-dimensional image that shows abnormalities or tumors. A CT scan is used to measure the size of the tumor and recognize enlarged lymph nodes, which may indicate the spread of cancer. Before the scan, a contrast medium dye delivers better detail to the image. This dye can be injected intravenously into the patient or given as a liquid to swallow. 
• Magnetic resonance imaging (MRI) – MRI uses magnetic fields to produce detailed body images. MRI can measure the tumor’s size and identify expanded lymph nodes, indicating that cancer has increased. A contrast medium dye is given before the scan to create a better picture. This dye can be given as a pill to swallow or injected into a patient’s vein. 

Positron emission tomography (PET) or PET-CT scan –  A PET scan is usually combined with a CT scan, called a PET-CT scan. Sometimes, it may be combined with MRI. A PET scan is a method to create multi-coloured images of organs and tissues inside the body. A small quantity of a radioactive substance is injected into the patient’s body which is taken up by cells using the most energy. The cancer cells which use energy actively take up the radioactive substance, and the scanner then spots this substance to produce images of the inside of the body. However, the quantity of radiation in the substance is designed to be too low to be harmful. A PET scanner then detects the substance to produce pictures of the inside of the body ^​5​.

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