A barium swallow is a test that involves drinking a thick white liquid called barium. Once you have swallowed the barium you will undergo a series of X-rays.
The barium coats the lining of your oesophagus so that it shows up on the X-ray. These X-rays are able to show your doctor whether there is an obstruction in your oesophagus, which may be an indication of a tumour.
You may have to undergo this test if your cancer has already been diagnosed, as it will help your doctor to assess the size of your tumour.
A barium swallow usually takes about 15 minutes to perform. After the procedure you will be able to eat and drink as normal, although you may need to drink more water to help flush the barium out of your system.