Background: CT-guided transthoracic needle biopsy is a well-established technique for the diagnosis of focal lung lesions. Fine needle aspiration biopsy (FNAB) requires the presence of a cytopathologist on-site to assess the adequacy of samples. For this reason FNAB is less and less used, and core biopsy is the first-line procedure when an experienced cytopathologist is not immediately available.
Purpose: To evaluate the accuracy and complication rate of CT-guided FNAB of lung lesions according to the experience of the cytopathologist on-site.
Material and methods: A total of 321 consecutive biopsies were considered. Immediate cytological assessment was performed by an experienced cytopathologist for the first 165 procedures (group A) and by two training pathologists for the remaining 156 biopsies (group B). At the time of FNAB the pathologist assigned a semiquantitative score (0-3) to each specimen to assess its diagnostic quality. All variables between the two groups were analyzed by chi-square and Student's t test. A P value <0.05 was considered statistically significant.
Results: For all procedures, overall diagnostic accuracy was 80% for cytology alone, with no statistical difference between the two groups for diagnostic accuracy and sample score assigned. In all, 75% of the cytological samples (75% group A, 74% group B) obtained a higher score with a specific diagnosis of histotype. A post biopsy pneumothorax was detected in 27% of biopsies (25% group A, 28% group B). Thirteen patients (4.0%) required chest tube insertion for treatment. For all cases, the pneumothorax rate was significantly affected by the number of samples obtained (P=0.02), but not by the pleural punctures (P=0.15). There was no statistically significant difference between the two groups concerning the number of needle passes and complication rate (P>0.05).
Conclusion: The efficacy and safety of CT-guided FNAB is not significantly affected by the training level of the cytopathologist on-site. Moreover, the number of specimens obtained for each procedure is a risk factor for pneumothorax.