Immune checkpoint inhibitor-induced diarrhea/colitis: Endoscopic and pathologic findings

Table 2 Definition of diarrhea and colitis based on Common Terminology Criteria for Adverse Events v5.0[32]

CTCAE Term	Definition	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5	CTCAE v5.0 Change
Diarrhea	A disorder characterized by an increase in frequency and/or loose or watery bowel movements	Increase of < 4 stools per day over baseline; mild increase in ostomy output compared to baseline	Increase of 4-6 stools per day over baseline; moderate increase in ostomy output compared to baseline; limiting instrumental ADL	Increase of ≥ 7 stools per day over baseline; hospitalization indicated; severe increase in ostomy output compared to baseline; limiting self-care ADL	Life-threatening consequences; urgent intervention indicated	Death	Clarification: Grade 2, 3, Definition
Colitis	A disorder characterized by inflammation of the colon	Asymptomatic; clinical or diagnostic observations only; intervention not indicated	Abdominal pain; mucus or blood in stool	Severe abdominal pain; peritoneal signs	Life-threatening consequences; urgent intervention indicated	Death	Addition: Navigational note; Clarification: Grade 3

ADL: Activities of daily living; CTCAE: Common Terminology Criteria for Adverse Events.