People who are suspected to have the lung disease idiopathic pulmonary fibrosis may not have to undergo biopsies, as clinical and radiological results should provide a confident diagnosis, according to a new study published in The Lancet Respiratory Medicine journal.
There is no cure for IPF and most people will only survive for 3 to 5 years following diagnosis. The disease causes scarring of the lungs, which worsens over time, until the lungs are unable to supply the required levels of oxygen to the rest of the body,
About 50,000 new cases of idiopathic pulmonary fibrosis (IPF) are diagnosed in the US each year. The mortality rates associated with IPF are comparable to the rates of death from breast cancer, as the disease kills 40,000 Americans each year. Studies also suggest that IPF is becoming more common.
High resolution computed tomography (HRCT) is used to identify IPF, as the disease often leaves a characteristic "honeycomb" scarring pattern, known as usual interstitial pneumonia (UIP). Currently, when IPF is suspected in a patient but there is no sign of the UIP pattern, international guidelines recommend that a biopsy be taken to confirm the diagnosis.
But taking a biopsy from the lung is a risky procedure. As Prof. Ganesh Raghu, who led the research behind the new study, explains: "Surgical lung biopsy is associated with substantial risks and many patients are too elderly, sick, and/or have comorbid conditions to tolerate the invasive procedure."
"A confident diagnosis of IPF is needed to ensure that patients are well informed of the poor prognosis associated with IPF, are treated with the most appropriate therapies, consider participation in clinical trials of new therapies, and to identify those most suitable for lung transplantation."
Are biopsies always necessary?
Prof. Raghu and team wanted to see if IPF could be accurately diagnosed in patients who do not exhibit UIP from HRCT scans, without the need for a biopsy.
To test this, the team showed expert radiologists and pathologists HRCT scans of 315 patients who had previously been suspected of IPF - but who presented with little or no visible honeycombing.
The experts were able to diagnose with 94% accuracy the patients who had IPF but whose scans exhibited little or no scarring. The researchers knew that the experts' diagnoses were accurate, as they also had access to results of the patients' biopsies.
Prof. Raghu says:
"Our findings suggest that when a team of multidisciplinary experts in interstitial lung disease at a regional center (that includes a chest radiologist and a pulmonologist) work together to interpret possible UIP pattern on high-resolution CT in a patient suspected to have IPF, surgical lung biopsy might not be necessary to reach a diagnosis of IPF."
However, Prof. Raghu warns that - because of the retrospective nature of the study and the way that cases were selected - results in day-to-day clinical settings may not be the same:
"Since the patients enrolled in our study were a highly selected cohort of patients suspected to have IPF and referred to regional sites for consideration of participation in a clinical trial, the findings from our study must not be extrapolated for all patients demonstrating the possible UIP pattern on HRCT images interpreted by general pulmonologists and radiologists in the community."
Experts predict that the role of lung biopsy will diminish, with lung disease diagnoses more likely to come from non-invasive techniques such as multidisciplinary meetings in conjunction with HRCT.