What is the treatment for radiation pneumonitis?

Treatment of Radiation Pneumonitis

Corticosteroids are the cornerstone of treatment for radiation pneumonitis, with oral prednisone 1 mg/kg daily recommended for grade 1-2 pneumonitis and high-dose intravenous methylprednisolone (2-4 mg/kg/day) for grade 3-4 pneumonitis. 1

Diagnosis and Assessment

• Radiation pneumonitis typically occurs 2-6 months after radiotherapy completion, presenting with nonproductive cough, exercise-induced dyspnea, low-grade fever, and chest pain 2, 1
• Differential diagnosis should include pulmonary infections, COPD exacerbations, heart failure, and immunotherapy-induced lung changes, which account for approximately 45% of post-radiation respiratory symptoms 2, 1
• Ambulatory pulse oximetry can aid in diagnosis - patients with radiation pneumonitis show a significant drop between resting and ambulatory pulse oximetry values compared to those without pneumonitis 3
• Bronchoscopy with bronchoalveolar lavage is recommended in grade 2 or higher pneumonitis to rule out infection before initiating immunosuppressive therapy 1

Treatment Algorithm Based on Severity

Grade 1-2 (Mild to Moderate) Pneumonitis:

• Initiate oral prednisone 1 mg/kg daily or equivalent 1
• Continue initial dose for 2 weeks, followed by a gradual, weekly taper (approximately 10 mg prednisone decrease per week) 4
• Consider gastroprotection during steroid treatment 4
• For patients with good performance status (ECOG ≤1), high-dose inhaled steroids (budesonide 800 μg twice daily) may be considered as an alternative initial treatment 5
• If no significant improvement within two weeks of inhaled steroid therapy, switch to oral prednisolone 5

Grade 3-4 (Severe) Pneumonitis:

• Hospitalize patient immediately 1
• Initiate high-dose intravenous corticosteroids (methylprednisolone 2-4 mg/kg/day) for 3 days 1, 4
• After IV treatment, transition to oral corticosteroids with a slow taper over at least 6 weeks 1, 4
• For steroid-refractory cases, cyclosporin A may be considered as a second-line treatment option 6

Supportive Care Measures

• Provide symptomatic treatment with inhaled β2-mimetics for bronchodilation 2, 1
• Administer oxygen supplementation as needed for hypoxemia 2, 1
• Consider prophylactic antibiotics for Pneumocystis pneumonia in patients receiving prolonged corticosteroid therapy (≥20 mg prednisone daily for ≥4 weeks) 1
• Add calcium and vitamin D supplementation with prolonged steroid use to prevent osteoporosis 1
• Strongly encourage smoking cessation, which is associated with decreased cough and dyspnea 2, 1

Monitoring and Follow-up

• Assess patients clinically every 2-3 days initially for grade 2 pneumonitis 1
• Monitor weekly with history, physical examination, and pulse oximetry 1, 3
• Perform repeat chest imaging in 3-4 weeks or sooner if symptoms worsen 1
• Taper steroids very slowly and carefully over 6 weeks or more, as relapses during tapering have been reported 1
• Monitor for steroid-related side effects and provide appropriate management 1

Special Considerations

• Patients with pre-existing interstitial lung disease require more intensive monitoring and counseling about their elevated risk 2, 1
• Patients receiving immunotherapy require special attention as the combination with radiation may increase pulmonary toxicity 2
• Permanently discontinue immunotherapy if it was the cause of pneumonitis 1
• If immunotherapy must be continued, delay reintroduction until prednisone dose is ≤10 mg daily 1

Prevention Strategies

• Careful radiation treatment planning to minimize the volume of lung receiving high doses 2
• The volume of lung receiving 5 Gy (V5) of the contralateral lung strongly correlates with pneumonitis risk 2
• Mean lung dose (MLD) and V20 (percentage of lung volume receiving ≥20 Gy) should be kept below upper limits (V20 of 35-37% or MLD of 20-23 Gy) 1