Transthoracic needle aspiration biopsy for the diagnosis of localised pulmonary lesions: a meta-analysis

Background-Persisting controversy surrounds the use of transthoracic needle aspiration biopsy (TNAB) stemming from its uncertain diagnostic accuracy. A systematic review and meta-analysis was therefore conducted to evaluate t he accuracy of TNAB for the diagnosis of solitary or multiple localised pul monary lesions. Methods-Searches for English literature papers in Index Medicus (1963-1965) and Medline (1966-1996) were performed and the bibliographies of the retri eved articles were systematically reviewed. Articles evaluating the accurac y of TNAB in series of consecutive patients presenting with solitary or mul tiple pulmonary lesions were considered. Only papers in which greater than or equal to 90% of patients were given a final diagnosis according to an ap propriate reference standard were included in the meta-analysis. Results-A total of 48 studies were included and five meta-analyses were con ducted according to four diagnostic thresholds. From the pooled sensitivity and specificity corresponding to each diagnostic threshold, associated lik elihood ratios (LRs) were derived for malignant disease as follows: (1) mal ignant versus all other categories, LR = 72; (2) malignant or suspicious ve rsus all others, LR = 49; (3) suspicious versus all categories but malignan t, LR = 15; (4) benign versus all others, LR = 0.07; and (5) specific benig n diagnosis versus all others, LR = 0.005. Differences in methodological qu ality of the studies, needle types, or whether a cytopathologist participat ed in the procedure failed to explain the heterogeneity of the results foun d in almost every metaanalysis. Given a 50% probability of malignancy prior to the TNAB, post-test probabilities of malignancy upon receiving the resu lts would be malignant, 99%; suspicious, 94%; non-specific benign, 7%; and benign with a specific diagnosis, 0.6%. Conclusions-Given the intermediate pre-test probabilities that would probab ly lead to performing TNAB, findings of "malignant" or of a specific diagno sis of a benign condition provide definitive results. Findings of "suspicio us" markedly increase the probability of malignancy, and "benign" markedly decreases it but may not be considered definitive.