Possible spread

Hi my husband was diagnosed with the return of his oesophageal cancer October, he had a stent fitted to help him eat. All was well until April and the food started sticking again. He had an endoscopy last week and apparently the stent is narrowing halfway down, so we’re thinking that the cancer has spread although this has not been confirmed.  Has anybody heard if it’s possible to have more than 1 tumour in the oesophagus