What is the treatment for radiation pneumonitis?

Treatment of Radiation Pneumonitis

The treatment of radiation pneumonitis consists primarily of corticosteroids, with prednisone 1 mg/kg daily (or equivalent) being the standard first-line therapy, tapered over 4-6 weeks for grade 1-2 pneumonitis, and higher doses of intravenous methylprednisolone (2-4 mg/kg/day) for grade 3-4 cases. 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 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 1
• COVID-19 testing is essential before starting corticosteroids in suspected radiation pneumonitis cases, as corticosteroids may exacerbate COVID-19-associated lung injury 2
• 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 treatment for 2 weeks at initial dose, then taper over 4-6 weeks 1, 3
• Monitor clinically every 2-3 days initially and consider radiological assessment 1
• Delay reintroduction of immunotherapy (if applicable) until prednisone dose is ≤10 mg daily 1

Grade 3-4 (Severe) Pneumonitis:

• Hospitalize patient immediately 1
• Initiate high-dose intravenous corticosteroids (methylprednisolone 2-4 mg/kg/day) 1
• Consider intravenous methylprednisolone for 3 days before transitioning to oral corticosteroids 3
• If no improvement after 48-72 hours, consider additional immunosuppressive strategies 1
• Options for steroid-refractory cases include infliximab, mycophenolate mofetil, cyclophosphamide, or cyclosporin A 1, 4
• Permanently discontinue the immunotherapy treatment if it was the cause 1

Supportive Care

• Provide symptomatic treatment with inhaled β2-mimetics and oxygen supplementation as needed 1
• Consider prophylactic antibiotics for Pneumocystis pneumonia in patients receiving prolonged corticosteroid therapy (≥20 mg prednisone daily for ≥4 weeks) 5
• Add calcium and vitamin D supplementation with prolonged steroid use 5
• Consider gastroprotection when using high-dose corticosteroids 3
• Encourage smoking cessation, which is associated with decreased cough and dyspnea 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 5
• Perform repeat chest imaging in 3-4 weeks or sooner if symptoms worsen 5
• Taper steroids very slowly and carefully over 6 weeks or more, as relapses during tapering have been reported 1

Special Considerations

• Patients with pre-existing interstitial lung disease require more intensive monitoring and counseling about their elevated risk 1
• The mean lung dose (MLD) and V20 (percentage of lung volume receiving ≥20 Gy) correlate with pneumonitis risk; V20 of 35-37% or MLD of 20-23 Gy are considered upper limits 1
• Lipoxygenase inhibitors and leukotriene receptor antagonists may offer protection against radiation pneumonitis mortality in experimental models 6
• A multidisciplinary approach involving both oncologists and pulmonologists is recommended for optimal management 3