Using this method, we have found that the prevalence of LAM is higher than that previously recorded and that many patients with LAM are undiagnosed.

Our population-based study showed that the median survival in patients with LAM from the onset of symptoms or diagnosis is much longer than previously described. This has important implications for life choices and treatment decisions regarding medication use and lung transplantation for patients with LAM.

Pulmonary lymphangioleiomyomatosis (LAM) is a rare cystic lung disease that targets women during their reproductive years. A confident diagnosis can often be based on clinical grounds, but diagnostic certainty requires pathological analysis. Although surgical lung biopsy is considered the gold standard for obtaining tissue in patients with diffuse lung disease, it is also associated with higher morbidity and mortality than alternative, less invasive techniques. The objective of our study was to examine the utility of transbronchial biopsy in the diagnosis of LAM. We conducted two online surveys of over 1,000 LAM patients registered with the LAM Foundation who were accessible by email. Transbronchial biopsy specimens were subsequently collected and reviewed by an expert pathologist to validate the diagnosis. We found that transbronchial biopsy has a yield of approximately 60% in patients with LAM. We conclude that transbronchial biopsy may be a safe and effective method for establishing the diagnosis of LAM, obviating the need for surgical lung biopsy in more than half of LAM patients.

Summary Background Lymphangioleiomyomatosis (LAM) is a rare, progressive and frequently lethal cystic lung disease that almost exclusively affects women and has no proven therapies. An improved understanding of the pathogenesis has identified promising molecular targets for clinical trials. Although barriers, modifiers, and benefits for clinical trial participation in common diseases such as cancer have been studied, we are unaware of such evaluations concerning rare diseases. Methods We performed a survey of a population-based registry of 780 LAM subjects in North America to identify predictors of trial participation. Logistic regression analysis evaluated the association of demographic and clinical features with trial participation. Results 41 of 263 (16%) LAM patient respondents in North America had participated in a clinical trial. Age, disease duration, lack of any college education, use of oxygen therapy, and presentation without chest pain were associated with trial participation in unadjusted analyses. Multivariate analyses indicate that patient age was the strongest independent predictor for trial participation (OR = 2.07, p = 0.004 per decade greater of patient age). Common reasons reported against trial participation included not meeting enrollment criteria (44%), drug toxicity (25%), and stable disease (20%). The most frequent reason reported for trial participation was to help future patients (85%). Conclusions Study entry criteria, drug toxicity, and stability of disease are barriers to trial enrollment among subjects with LAM. Older LAM patients and those with more advanced disease are more likely to have participated in clinical trials. Altruism is commonly a motivating factor.

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