PURPOSE: Endobronchial ultrasound (EBUS) transbronchial needle aspiration (TBNA) changes the conventional TBNA procedure by removing sampling uncertainties, and enabling puncture of smaller and previously difficult to access lymph nodes. As the practice of EBUS bronchoscopy becomes more widely accepted, it has also revived a longstanding question on the optimum size of the biopsy needle. Previous comparative studies suggested that for conventional TBNA, larger needles (19-gauge) might provide more biopsy material and thus an increased chance of improved diagnostic yield over smaller needles (22-gauge).
METHODS: We conducted a randomized study using EBUS TBNA to compare the diagnostic yield of the 22-gauge to the 19-gauge needles. One hundred ninety nine patients were enrolled. Selection of these patients was based on positive chest CT scan. Lung cancer to non-lung cancer patient ratio was about 1.5. Lymph nodes were identified by EBUS and TBNA was performed. Lymph nodes sampled included left and right sided stations 2, 4, and 10 as well as stations 3 and 7. Non-cancer cases included sarcoidosis, lymphoma, infection and inflammation.
RESULTS: Study results show that in our selected population, the 22-gauge needle has a diagnostic yield of about eighty-one percent as compared to the 19-gauge needle of eighty-nine percent. In the subgroup analysis of only lung cancer patients the diagnostic yield of the 22-gauge and 19-gauge needles are eighty-eight percent and eighty-nine percent respectively; the false negatives are twelve percent and ten percent respectively.
CONCLUSION: The yield of the 19-gauge needle appears to be superior to the 22-gauge needle for EBUS TBNA especially in the evaluation of mediastinaum lymph nodes in non-cancer patient. However, the difference becomes insignificant in lung cancer patients.
CLINICAL IMPLICATIONS: For EBUS TBNA mediastinum lymph node assessment of non-cancer patient, the 19-gauge needle appears to be the needle of choice. Nonetheless, for lung cancer patient, the 22-gauge needle may provide comparable diagnostic yield. Rapid onsite cytology evaluation may further reduce their differences.
DISCLOSURE: Kelvin Shiu, None.