Use of ultrasound localization to improve results of fine needle aspiration cytology of breast masses.

A prospective randomized controlled trial of 116 patients with breast masses was conducted to compare the accuracy of 'blind' aspiration cytology performed in the clinic with aspiration cytology using ultrasound localization. The unsatisfactory aspiration cytology rate was significantly reduced by ultrasound localization (P = 0.028). This was mainly due to an improvement in the unsatisfactory rate for tumours less than 3 cm in diameter (P = 0.036). The results were influenced by the number of needle manoeuvres performed, less than 10 needle manoeuvres being associated with a 54% unsatisfactory aspiration rate compared with 25% when greater than 10 manoeuvres were performed (P = less than 0.02). One experienced aspirator in the clinic had results comparable to those achieved with ultrasound localization. It is concluded that experience and technique are the most important factors in obtaining a satisfactory aspirate from breast masses. Routine ultrasound localization prior to aspiration confers some benefit. Consideration should be given to the use of the ultrasound-assisted technique following a previous unsatisfactory aspiration, particularly if the tumour is less than 3 cm in diameter.