Biopsy for lung-scarring disorder may be avoidable

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Biopsy for lung-scarring disorder may be avoidable

Expertly read high-resolution CT scans may be sufficient to confirm diagnosis of idiopathic pulmonary fibrosis
Marsha Rule

A risky surgical lung biopsy might not be needed to confirm idiopathic pulmonary fibrosis in patients suspected of having the deadly disorder, but whose lung scans don’t readily reveal a telltale honeycombing pattern.

Clinical and radiological findings alone, when carefully interpreted by experts in interstitial lung disease, could provide a confident diagnosis, according to a report in The Lancet Respiratory Medicine.

Dr. Ganesh Raghu, University of Washington professor of medicine, Division of Pulmonary and Critical Care Medicine, and director of  UW Medicine’s Center for Interstitial Lung Disease, led the multi- center, multi-national study. The team wanted to determine if idiopathic pulmonary fibrosis could be accurately diagnosed with high-resolution CT in patients who had little or no radiological evidence of honeycombing.

He explained that idiopathic pulmonary fibrosis causes progressive scarring of the lungs. “Idiopathic” means the underlying cause is not known.  The disease has no cure as yet.  Most people with the condition live only three to five years after diagnosis.  During the course of the disease, shortness of breath worsens. Eventually the lungs can no longer supply enough oxygen to the rest of the body.

There are about 50,000 new cases of idiopathic pulmonary fibrosis detected each year. The disease kills as many as 40,000 people annually. The disease is being detected and diagnosed  more often  in the United States lately .  Raghu said that this apparent higher prevalence may be due to more liberal use of high-resolution CT scans of the chest for diagnostic interventions in patients with persistent shortness of breath on exertion .
Present evidence-based guidelines for diagnosis and management of idiopathic pulmonary fibrosis from 2011 emphasize the requirement of surgical sampling of lung  tissue  — a biopsy obtained under general anesthesia —from the patient’s lungs, if high-resolution CT scans are not definitive.

In general, high-resolution CT scans of the lungs can identify the honeycombing pattern of lung scarring and the air sac damage known as usual interstitial pneumonia in people with idiopathic pulmonary fibrosis. When the pattern is definitive  surgical lung biopsy is not needed in patients who do not have environmental exposures and other diseases that may also show similar patterns in the high resolution CT scans of the chest.

High-resolution CT scan of the lungs.
Clare McLean
High-resolution CT scan of the lungs.
High-resolution CT scan of the lungs.

In an adult who suffers from increasing breathlessness, but who has neither environmental exposures responsible for the buildup of fibrous tissue in the lungs, nor evidence of collagen vascular diseases such as rheumatological or autoimmune disorders, the precise honeycombing  pattern of usual interstitial pneumonia  is sufficient to make a diagnosis of idiopathic pulmonary fibrosis.  When patients suspected of having the condition don’t showthe usual interstitial pneumonia pattern on their CT scans, then a lung biopsy is usually ordered.

Specimens obtained from more than one lobe increase diagnostic accuracy.  The samples are examined for certain abnormalities in damaged air sacs.

A near-certain diagnosis is essential. Raghu said it allows doctors to inform the patient of the poor prognosis, treat with the  most appropriate therapies, help enroll qualified participants in clinical trials of new therapies, and pick out those most suitable for lung transplantation surgery.

However, lung biopsies  are major surgery and carry substantial risks, Raghu said. These dangers are heightened in people who are elderly or sick, or who have other serious conditions that make the procedure difficult to tolerate. Most patients with idiopathic pulmonary fibrosis are above 60 years of age and have other medical problems that may pose additional risks with surgery.

Raghu led a retrospective study of 315 patients age 40 and older. They were originally screened for the failed ARTEMIS-IPF trial. These patients had records of both high-resolution CT scans and surgical biopsy samples. Raghu’s study focused on the predictive value of a radiological diagnosis of possible usual interstitial pneumonia in patients without the presence of the honeycomb pattern.

The predictions were checked against the results of the surgical biopsy.  Of the 84 patients who had a high-resolution pattern of possible usual interstitial pneumonia diagnosed by an expert radiologist and pathologist, in 79, or 94 percent, the analysis of the lung biopsy samples confirmed the prediction.

In a press release issued by The Lancet, Raghu said, “Our findings suggest that when a regional medical center team of multidisciplinary interstitial lung disease experts, including a chest radiologist and a pulmonologist, work together to interpret possible usual interstitial pneumonia patterns on a high-resolution CT scan of a patient suspected to have idiopathic pulmonary fibrosis, then surgical lung biopsy may not be necessary to reach a diagnosis of this condition.”

Raghu cautioned against applying the findings to other medical settings and patient populations:

“Because the patients enrolled in our study were a highly selected cohort of patients suspected to have idiopathic pulmonary fibrosis, and referred to regional sites for consideration of participation in a clinical trial, the findings from our study should not be extrapolated for all patients demonstrating the possible usual interstitial pneumonia patterns on high-resolution CT images interpreted by general pulmonologists and radiologists in the community.”

Gilead Sciences sponsored The ARTEMIS-IPF trial.