Fine needle aspiration of hepatic colorectal metastases

Editor—That the BMJ decided to publish the lesson of the week by Metcalfe et al with an eye catching title smacking of tabloid journalism is most surprising.¹ To dismiss outright as useless and dangerous the procedure of fine needle aspiration of suspected colorectal metastases will raise serious doubts in the minds of many clinicians of the safety of this procedure, not only in colorectal metastases but in any liver metastases. It certainly has medicolegal implications for people who perform fine needle aspiration of any malignant lesion.

There have been recent examples of chaos and confusion caused in the minds of the public and the medical profession resulting from publications based on inadequate, inaccurate, or biased data. Many in this country have performed several hundreds of fine needle aspirations and percutaneous biopsies without such a high rate of tumour seeding, allowing for the fact that we may not be aware of all such complications.

Some of the current practices adopted are likely to give rise to a higher incidence of seeding. Use of serrated needle tips, which enhances visibility of the needle, may trap tumour cells and deposit them along the route. Multiple passes, especially if performed with the same needle, could be blamed. I have always encouraged the use of a generously wide port for the entry site to prevent the cells being “wiped” off the needle when the needle is withdrawn. Penetration deep into the tumour may contaminate a longer length of the needle. The needle calibre may have a bearing.

Oncologists are highly unlikely to treat on the basis of diagnosis based on imaging alone. Few radiologists would claim a high degree of accuracy except in a few tumours. May I therefore suggest that guidelines for best practice be formulated for reducing this and other complications encountered with fine needle aspiration and biopsies by using any form of image guidance.