What does a CT chest scan showing unchanged bibasilar predominant atelectasis/scarring with mild bilateral traction bronchiectasis mean for a breast cancer patient on Kisqali (ribociclib) experiencing shortness of breath?

CT Findings of Bibasilar Atelectasis/Scarring with Traction Bronchiectasis in a Breast Cancer Patient on Kisqali

The CT findings of unchanged bibasilar predominant atelectasis/scarring with mild bilateral traction bronchiectasis likely represent prior lung injury from an infectious or inflammatory process and are unlikely related to Kisqali therapy. The recommended next step is pulmonary function testing to assess respiratory function, followed by close monitoring of symptoms without discontinuing Kisqali.

Interpretation of CT Findings

Understanding the Radiological Features

• Bibasilar atelectasis/scarring: Represents areas of lung collapse or fibrotic changes in the lower portions of both lungs 1, 2
• Traction bronchiectasis: Irreversible dilatation of bronchi caused by surrounding fibrotic tissue pulling on the airways 1, 3
• "Unchanged": This is a critical finding indicating stability rather than progression, suggesting these are chronic changes rather than an acute process 1

Clinical Significance

• These findings typically represent sequelae of prior infectious or inflammatory processes rather than active disease 4
• Traction bronchiectasis is characterized by bronchial dilatation due to surrounding fibrotic tissue, distinguishing it from other forms of bronchiectasis 1, 3
• The stable nature of these findings suggests they are unlikely the primary cause of new shortness of breath 1

Relationship to Kisqali (Ribociclib)

Drug-Related Considerations

• Kisqali can cause interstitial lung disease (ILD)/pneumonitis in 1.5-1.6% of patients, which is a serious potential complication 5
• However, ILD/pneumonitis from Kisqali typically presents as:
  • New or progressive ground-glass opacities
  • New areas of consolidation
  • Progressive respiratory symptoms
  • Not typically as stable bibasilar scarring with traction bronchiectasis 1, 5

Risk Assessment

• The unchanged nature of the CT findings makes drug-induced pneumonitis less likely 1, 5
• Stable traction bronchiectasis is more consistent with prior lung injury rather than an active drug reaction 1, 3

Recommended Management Approach

Initial Assessment

1. Evaluate respiratory symptoms:

   • Determine if shortness of breath is new, progressive, or stable
   • Assess for associated symptoms (cough, fever, sputum production)
   • Measure oxygen saturation at rest and with exertion 1, 6

2. Pulmonary function testing:

   • Complete PFTs to evaluate for restrictive or obstructive patterns
   • Diffusion capacity testing to assess gas exchange 1

Further Management

1. If symptoms are mild and stable:

   • Continue Kisqali therapy with close monitoring
   • Consider bronchodilator therapy if there is evidence of airflow obstruction 1, 6

2. If symptoms are progressive or severe:

   • Consider high-resolution CT (HRCT) to better characterize the lung abnormalities
   • Evaluate for potential infectious causes with appropriate cultures 1

3. Kisqali management:

   • Continue Kisqali if symptoms are mild and CT findings remain unchanged
   • Consider interrupting Kisqali only if there is evidence of new or worsening ILD/pneumonitis 5

Special Considerations

When to Suspect Drug-Induced Pneumonitis

• New or worsening respiratory symptoms
• New ground-glass opacities or consolidation on CT
• Exclusion of infectious causes 1, 5

Monitoring Recommendations

• Follow-up CT in 3-6 months if symptoms persist or worsen
• Regular assessment of respiratory symptoms during Kisqali therapy
• Pulse oximetry monitoring with activity 1

When to Consider Discontinuing Kisqali

• Development of new ground-glass opacities or consolidation
• Progressive respiratory symptoms with declining oxygen saturation
• Confirmation of drug-induced pneumonitis 5

The stable nature of the CT findings in this case suggests that the current shortness of breath may be due to another cause or represent a mild exacerbation of underlying lung disease rather than a drug-related adverse event.