Immune-Related Adverse Events (irAE) -- GI Toxicity Colitis Grading
CTCAE-based grading of immune-related colitis caused by checkpoint inhibitor immunotherapy (anti-PD-1, anti-PD-L1, anti-CTLA-4). Guides immunotherapy hold/discontinuation and corticosteroid management.
Score interpretation
CTCAE Grade 1 immune colitis -- mild symptoms; immunotherapy usually continued or held temporarily
→ Continue the checkpoint inhibitor or hold it temporarily (oncology decision); adults: loperamide 4 mg initial then 2 mg after each loose stool (max 16 mg/day); hydration; low-fibre diet; stool culture to exclude infection (C. difficile, CMV, salmonella, campylobacter); flexible sigmoidoscopy or colonoscopy if symptoms persist > 7 days; systemic steroids NOT required at Grade 1; resume immunotherapy when symptoms resolve to Grade 0-1 after washout; document grade and date in oncology notes; oncology team notification. Children: use a children's formulary.
CTCAE Grade 2 -- moderate immune colitis; hold immunotherapy and start corticosteroids
→ Hold checkpoint inhibitor permanently (CTLA-4) or temporarily (anti-PD-1) -- oncology team decision; adults: prednisolone 1 mg/kg/day orally (or IV methylprednisolone); stool cultures; CMV PCR (blood and biopsy); colonoscopy if no improvement in 48-72 hours; treat CMV colitis with ganciclovir if detected; taper steroids over 4-6 weeks once Grade 1 or better; PPI and calcium/vitamin D during steroid course; gastroenterology liaison; budesonide MMX (adults: 9 mg OD) may be added (topical steroid for colonic inflammation); consider infliximab (adults: 5-10 mg/kg IV) if steroid-refractory. Children: use a children's formulary.
CTCAE Grade 3-4 -- severe or life-threatening immune colitis; permanently discontinue immunotherapy
→ PERMANENTLY discontinue checkpoint inhibitor; IV methylprednisolone (adults: 1-2 mg/kg/day); hospital admission; urgent gastroenterology and oncology review; CT abdomen/pelvis to exclude perforation, toxic megacolon; urgent flexible sigmoidoscopy; stool and blood cultures; IV fluid resuscitation; nil by mouth if severe; infliximab (adults: 5 mg/kg IV) within 48-72 hours if no improvement on steroids (or vedolizumab — adults: 300 mg IV — as alternative if concerns about infliximab -- gut-selective); surgical referral if perforation signs (colectomy may be required); colostomy consideration for Grade 4; ICU if haemodynamically compromised; taper IV steroids to oral over 4-6 weeks after improvement; long-term gastroenterology follow-up (some develop IBD-like condition); document all management in oncology notes. Children: use a children's formulary.
Interpretation bands for the irAE GI Colitis. Apply clinical judgement and local guidance.
References
- Puzanov I et al. Managing toxicities associated with immune checkpoint inhibitors: consensus recommendations from the Society for Immunotherapy of Cancer (SITC) Toxicity Management Working Group. J Immunother Cancer. 2017;5(1):95.
- ESMO Clinical Practice Guidelines for the management of toxicities from immunotherapy. Ann Oncol. 2017;28(Suppl 4):iv119-iv142.
Related
Curated clinical cross-links plus same-class fallbacks.
- Pembrolizumab · Anti-PD-1 monoclonal antibody (immune checkpoint inhibitor)
- Atezolizumab · Anti-PD-L1 Monoclonal Antibody — Immune Checkpoint Inhibitor (Specialist Oncology Drug)
- Avelumab · Anti-PD-L1 Monoclonal Antibody — Immune Checkpoint Inhibitor (Specialist Oncology Drug)
- Pembrolizumab · PD-1 Immune Checkpoint Inhibitor
- Ipilimumab (Specialist drug) · Anti-CTLA-4 monoclonal antibody (immune checkpoint inhibitor)
- Nivolumab (Specialist drug) · Anti-PD-1 immune checkpoint inhibitor
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.