From the Guidelines
Features associated with poor prognosis in lymphangioleiomyomatosis (LAM) include rapid decline in lung function, severe airflow obstruction, reduced diffusion capacity, presence of chylous effusions, and extensive cystic changes on high-resolution CT scans, as noted in the official American Thoracic Society/Japanese Respiratory Society clinical practice guidelines 1.
Key Prognostic Factors
- Rapid decline in lung function, particularly FEV1 decline greater than 90 ml/year
- Severe airflow obstruction
- Reduced diffusion capacity
- Presence of chylous effusions
- Extensive cystic changes on high-resolution CT scans
- Younger age at diagnosis (typically under 35 years) and premenopausal status, which are linked to more aggressive disease progression, likely due to estrogen's role in stimulating LAM cell proliferation 1
- Patients with tuberous sclerosis complex (TSC)-associated LAM often have a more favorable prognosis than those with sporadic LAM
- Higher serum vascular endothelial growth factor D (VEGF-D) levels (>800 pg/ml) correlate with more extensive disease and faster progression, as suggested by the guidelines for using VEGF-D as a diagnostic test 1
Management Strategies
- Early recognition of these poor prognostic factors can help guide more aggressive management strategies, including earlier consideration for mTOR inhibitors like sirolimus, which can slow disease progression, as recommended by the guidelines 1
- Evaluation for lung transplantation in appropriate candidates, considering factors such as severe airway obstruction, reduced diffusion capacity, and hypoxemia at rest, as outlined in the European Respiratory Society guidelines 1
From the Research
Features Associated with Poor Prognosis in LAM
- Poor lung function parameters, such as forced vital capacity, forced expiratory volume in 1 second, and diffusing capacity for carbon monoxide, are associated with a poor prognosis in LAM patients 2.
- The presence of chylous effusions and lymphangioleiomyomas can also indicate a poor prognosis, although treatment with sirolimus has been shown to improve or stabilize lung function and reduce the size of these conditions 3, 4.
- A rapid decline in lung function, with an annual drop in FEV1 of 75 to 120 mL, is also a feature of poor prognosis in LAM patients 5.
- Recurrent pneumothorax is a common complication of LAM and can contribute to a poor prognosis if not managed effectively 6, 5.
- The presence of renal angiomyolipomas, which can exceed 4 cm in size and are more likely to bleed, can also indicate a poor prognosis and require evaluation for embolization 5.