Objective:

To review the major life-threatening complications of cancer immunotherapy from an ICU perspective, focusing on recognition, differential diagnosis, and management.

Approach:

• Syndrome-based framework: Discussion of critical illness patterns associated with CAR-T therapy, immune checkpoint inhibitors, and bispecific T-cell engagers.
• Key topics covered: Cytokine release syndrome, HLH/MAS, immune effector cell-associated neurotoxicity syndrome, respiratory failure, cardiovascular emergencies, and other organ toxicities.
• Diagnostic conflicts: Summary of major diagnostic conflicts in the ICU and proposed principles for organ support, immunomodulatory therapy, and infection management.

Key Findings:

• Immunotherapy has introduced new ICU-relevant complications distinct from traditional critical illness patterns.
• Complications include hyperinflammatory syndromes, neurotoxicity, severe pneumonitis, myocarditis, and overlapping infectious complications.
• Recognition of these complications is complicated by their clinical overlap with sepsis, infection, and tumor progression.

Interpretation:

Limitations:

• The review does not summarize all immune-related adverse events, focusing instead on those most relevant to ICU admission.
• Current knowledge gaps regarding outcomes, rechallenge, and future research priorities remain.

Conclusion:

Immunotherapy-related critical illness is increasingly relevant in modern oncologic intensive care, necessitating a reassessment of ICU triage and treatment priorities.