Severe complications following intravesical BCG instillation

Area of Science:

• Oncology
• Pulmonology
• Immunology

Background:

• Intravesical Bacillus Calmette-Guérin (BCG) is a standard immunotherapy for non-muscle-invasive bladder carcinoma.
• BCG instillation aims to stimulate an immune response against tumor cells.
• While generally safe, BCG can cause systemic side effects.

Observation:

• Two cases of severe pulmonary complications following intravesical BCG treatment are presented.
• Patients developed significant respiratory distress and lung pathology during therapy.
• These cases highlight a serious but uncommon adverse event associated with BCG instillation.

Findings:

• The study explores potential etiological mechanisms for BCG-induced pulmonary toxicity.
• Mechanisms may involve direct BCG effects, immune-mediated responses, or cytokine storm.
• A novel classification system for intravesical BCG treatment side effects is proposed.

Implications:

• Understanding these severe pulmonary side effects is crucial for patient safety.
• Early recognition and management strategies for BCG-related lung injury are needed.
• The proposed classification may aid in standardizing reporting and research on BCG adverse events.