Does needle size affect diagnostic yield of transthoracic needle biopsy in malignant pulmonary lesions? Comparison of 18-, 22- and 25-gauge needles in surgical specimens.

Objective: To evaluate the effect of needle size on the diagnostic yield of transthoracic needle aspiration biopsy in malignant pulmonary lesions.

Methods: The study assessed samples from 35 patients who underwent surgery for lung cancer. We used surgical specimens for needle aspiration biopsy. Aspirations were performed with 25-, 22- and 18-gauge, 9 cm in length aspirating needles. All pathology preparations were coded. At the end of the study period, all needle aspiration preparations were interpreted by the same pathologist.

Results: Lobectomy was performed in 19 patients, pneumonectomy in 15 and bilobectomy in one. Squamous cell carcinoma was the most frequent tumour type, followed by adenocarcinoma. The diagnostic yield of aspiration biopsy was 85.7% for 18-gauge needle and 82.9% for both 22-gauge and 25-gauge needles. There was no statistically significant difference for the three needles with respect to diagnostic yield (P > 0.05). Cell type concordance for 18-, 22- and 25-gauge needles was 70%, 65.6% and 65.6%, respectively. There was no statistically significant difference for the three needles with respect to cell type concordance (P > 0.05).

Conclusion: Needle size did not affect diagnostic yield or accuracy for malignant lesions. Smaller needles such as 22-gauge needle would appear to be suitable for transthoracic needle aspiration biopsy in the diagnosis of malignant pulmonary lesions.