Evaluating intra-procedural cytological touch preparation in percutaneous lung biopsy

Due to the overall safety and efficacy of obtaining pathologic samples for histologic or molecular diagnosis, percutaneous lung biopsy (PLB) has become the primary means of characterizing suspicious nodules or masses within the lung. To limit morbidity and mortality associated with undergoing lung biopsies, real time touch prep (RTTP) cytological evaluation of biopsy samples is used at many institutions for an immediate assessment of tissue adequacy for diagnosis. We evaluate the outcomes and potential risks associated with RTTP.

Materials and Methods:

Single-center retrospective analysis of 460 consecutive patients who underwent PLB with RTTP

Results:

Major axis < 2cm was 254, minor axis < 2cm 288 vs 206 and 135 > 2 cm respectively. For lesions  < 2cm RTTP was non-adequate for diagnosis in 28.3% and 24% (Major vs minor) compared to 12.6% (p-values= < 0.001 and 0.006, respectively). With final histologic diagnosis (HD), lesion size was not a significant determinate. RTTP accuracy was influenced by pulmonary hemorrhage (PH); adequacy decreased from 83.9% to 73.4% with PH (p=0.006), no difference was seen in HD after PH. Procedure time (PT) was significantly decreased with an adequate RTTP, 46 min vs 56 min (p=< 0.001).  When adequacy was obtained RTTP the number of slides was also less 3.4 vs 3.8 (p-value=0.006). This increased number of slides was also associated with increased rate of chest tube placement (p =0.011). Changes in adequacy did not increased risk of pneumothorax (p-value=0.446) or PH (p-value=0.527).

Conclusion:

Lesions less than 2 cm in length are significantly less likely to produce adequate samples by RTTP. However, RTTP does not predict the ability of a pathologist to reach a conclusive final diagnosis, thus inconclusive RTTP might encourage a radiologist to obtain more samples unnecessarily, prolonging procedure time and increasing of slides obtained.