Study Question: Is needle biopsy guided by computed tomography (CT) more accurate than standard pleural biopsy in diagnosing malignant disease in patients with cytology-negative unilateral pleural effusions?
Setting: Inpatient (any location)
Study Design: Randomized controlled trial (nonblinded)
Synopsis: Patients referred to a single center with unilateral pleural effusions thought to be caused by malignancy and who had at least one previous negative pleural fluid cytology were randomly assigned (concealed allocation) to a standard Abrams' pleural biopsy (n = 25) or CT-guided biopsy with an 18-gauge cutting needle (n = 25). Researchers stratified the patients by the degree of pleural thickening before randomization. They do not mention whether the pathologists interpreting the specimens knew which technique was used. The gold standard here is a bit tarnished, but not unreasonable. When a malignant lesion was found on biopsy, the malignancies were confirmed.
At least one year later, investigators reevaluated the patients in whom no malignancy was detected. In the standard biopsy group, 17 patients (68 percent) ultimately were found to have a malignancy, eight of which were detected (sensitivity: 47 percent; specificity: 100 percent; positive likelihood ratio at infinity; negative likelihood ratio [LR–] = 0.5). In the CT-guided biopsy group, 15 patients (60 percent) had a malignancy, 13 of which were detected (sensitivity: 87 percent; specificity: 100 percent; LR– = 0.13). No complications occurred in the CT-guided group, and only one patient in the standard biopsy group developed a moderate-sized hematoma. In this study, although the authors report the population to have a low rate of asbestos exposure, 20 of the 33 malignancies identified were mesotheliomas.
Bottom Line: What should you do when a patient presents with a unilateral pleural effusion that you suspect is caused by an underlying malignancy, despite negative pleural cytology? Rather than referral to a pulmonologist or surgeon for a pleural biopsy, the patient should be referred for CT-guided needle biopsy. In this study, CT-guided needle biopsy was much more sensitive and, as with standard pleural biopsies, had very high specificity. (Level of Evidence: 1c)