What is the treatment for radiation pneumonitis?

Treatment of Radiation Pneumonitis

Corticosteroids are the mainstay of treatment for radiation pneumonitis, with patients with grade 2 pneumonitis requiring a minimum dose of 40 mg of prednisone daily, tapered over 8 to 10 weeks. 1

Diagnosis and Assessment

Radiation pneumonitis is characterized by:

• Typical onset: 2-6 months after radiotherapy completion 1
• Clinical symptoms: nonproductive cough, exercise-induced dyspnea, low-grade fever, and chest pain 1
• Radiographic findings: new or progressive pulmonary infiltrates and ground glass changes on CT imaging (more reliable than chest radiographs) 1

Diagnostic workup should include:

• Chest CT (imaging modality of choice)
• Pulmonary function tests (PFTs)
• Oxygen saturation monitoring (at rest and with ambulation)
• 6-minute walk test
• Ambulatory pulse oximetry (a decline between resting and ambulatory pulse oximetry levels can serve as a clinical aid in diagnosis) 2

Treatment Algorithm Based on Severity

Grade 1 (Asymptomatic)

• Drug withdrawal is the mainstay of treatment
• Close monitoring every 2-3 days
• Repeat chest CT prior to next scheduled treatment
• Consider bronchoscopy for new or persistent infiltrates
• May cautiously resume therapy if infiltrates resolve 1

Grade 2 (Symptomatic)

• Initiate corticosteroids at minimum 40 mg prednisone daily 1
• Taper over 8-10 weeks (minimum 4-6 week taper to avoid recrudescence) 1
• Consider outpatient management with close follow-up 1
• Symptomatic treatment:
  • Inhaled β2-mimetics
  • Oxygen supplementation as needed 1
• Consider high-dose inhaled steroids (budesonide 800 μg twice daily) in select patients with good performance status 3

Grade 3 or Higher (Severe)

• Hospitalization required
• For severe pneumonitis, IV methylprednisolone for 3 days before transitioning to oral corticosteroids 4
• For steroid-refractory cases (no improvement after >48 hours of corticosteroid therapy), consider:
  • Infliximab
  • Mycophenolate mofetil
  • Intravenous immune globulin (IVIG)
  • Cyclophosphamide 1, 5

Monitoring Treatment Response

• Monitor oxygen saturation (both resting and ambulatory)
• Repeat chest imaging to assess resolution of infiltrates
• Ambulatory pulse oximetry can help gauge treatment response, with peak recovery typically occurring after 2 weeks of corticosteroid therapy 2
• Continue monitoring for at least 6-12 months, as radiation-induced pulmonary fibrosis can develop during this timeframe 1

Special Considerations

• Recrudescence of pneumonitis signs and symptoms can occur with rapid steroid taper; therefore, a minimum 4-6 week taper is recommended 1
• Patients with pre-existing lung diseases (COPD, interstitial lung disease) require more intensive monitoring and counseling about increased risk 1
• Smoking cessation should be encouraged as it is associated with a decrease in cough and dyspnea 1
• Consider gastroprotection when initiating high-dose corticosteroid therapy 4
• In patients receiving immune checkpoint inhibitors, differentiation between radiation pneumonitis and immune-related pneumonitis may be challenging and may require different management approaches 1

Pitfalls and Caveats

• Failure to recognize and treat pneumonitis promptly can lead to poor clinical outcomes 1
• Rapid steroid taper can lead to symptom recurrence; gradual tapering is essential 1
• Alternative diagnoses should be considered, including:
  • Pulmonary infections
  • COPD exacerbations
  • Heart failure
  • Cardiac arrhythmias
  • Anemia
  • Lymphangitic spread of tumor 1
• Bronchoscopy with bronchoalveolar lavage may be necessary to exclude competing diagnoses, particularly infections 1