Table 1.

Grading of irAEs referring to the CTCAE v5.0.

Gastrointestinal disorders	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5
Diarrhea	Increase of less than 4 stools per day and mild increase in ostomy output compared with baseline.	Increase of 4–6 stools per day and moderate increase in ostomy output compared with baseline; limited instrumental ADLs.	Increase of more than 7 stools per day and severe increase in ostomy output compared with baseline; limited self-care ADL such as bathing, feeding and taking medications; hospitalization indicated.	Life-threatening consequences such as perforation, bleeding or toxic megacolon; urgent intervention indicated.	Death
Colitis	No clinical symptoms, but imaging changes may be present.	Mild or moderate abdominal pain as well as mucus or blood in stool.	Severe abdominal pain and peritoneal signs.	Life-threatening consequences such as perforation, bleeding or toxic megacolon; urgent intervention indicated.	Death