Objectives: The decision to perform lung biopsy in the evaluation of interstitial lung disease (ILD) is based on the probability that this examination will yield a specific diagnosis, leading to a change in treatment. The purpose of this study was to identify factors that influence the diagnostic yield of lung biopsy for ILD.
Methods: One hundred patients underwent lung biopsy for ILD over a 5-year period. There were 59 men and 41 women; with a median age of 51.5 years. Thirty percent underwent open lung biopsy, while 70% had videothoracoscopic biopsy. Patient and disease characteristics, prior diagnostic studies, pre-operative therapy, biopsy type, site, size, number, and laterality were compared to identify factors that might influence diagnostic yield.
Results: Forty-two percent had a specific diagnosis, while 58% had a non-specific diagnosis. Right side was selected in 57.1% of patients with a specific diagnosis and 48.3% of patients without a specific diagnosis (P=0.381). Right lower lobe was the main site for biopsy in the specific diagnosis group compared to the non-specific group (35.7 versus 20.7%, P=0.095). Left upper lobe was the main site for biopsy in the non-specific diagnosis group compared to the specific diagnosis group (41.4 versus 23.8%, P=0.067). Mean volume of biopsy was 12.3 cm(3) in the specific diagnosis group and 12 cm(3) in the non-specific diagnosis group (P=0.373). Two or more biopsies were carried out in 38.1% of the specific diagnosis group compared to 25.9% of the non-specific diagnosis group (P=0.192). There were no significant factors in predicting a diagnostic yield. Of those patients with a specific diagnosis, 59.5% had therapy altered, compared to 55.2% of those with a non-specific diagnosis (P=0.664).
Conclusions: Lung biopsy does not always provide a specific diagnosis and does not always change therapy. The site, size, number, and laterality of the biopsy specimen have no definite influence on diagnosis. There is a trend to improve diagnostic yield by carrying out two or more biopsies on the right lung.