Esophageal Stent

We have a friend with gastro-esophageal cancer who has been doing protocol 1000 and is ready to start protocol 2000.  About a week ago, he had an esophageal stent installed, which is helping him to eat and drink.

Is it safe for him to resume the protocols now that he is home from the hospital?  Or will the foreign substance (I don't know if the stent is metal or plastic, or both) interact with the CD?

Thank you