27th February 2025

A 56-year-old patient with non-small cell lung cancer is being treated with durvalumab immunotherapy

A 56-year-old patient with non-small cell lung cancer is being treated with durvalumab immunotherapy. He has no other past medical history. He has been struggling with two weeks of diarrhoea. He has been opening his bowels 10-12 times per day, passing liquid stool each time. For the last 3 days he has noticed blood in his stools. His stool cultures and Clostridium difficile screen are negative. He is admitted under the oncology team and is commenced on intravenous methylprednisolone 2 mg/kg and loperamide 4 mg QDS. 72 hours later, he complains of ongoing diarrhoea and tells you he has his bowels 9 times in the last 24 hours.

What is the most appropriate next step in management?

Select the SINGLE most appropriate option from the list below. Select ONE option only.