This week, I have been over in Washington DC at the ATA. It has been a great opportunity to network and learn from leaders in the field as well as to find out about cutting edge advances in thyroid cancer and thyroid disease.
One of the things I am most excited about is molecular testing. Currently in the UK, if you come and see me in my neck lump clinic you will have an ultrasound scan. Many of these will show benign nodules with no further action needed and I can often reassure and discharge you on the same day. Many people, however, will have a thyroid nodule that does not appear normal. A small number of these will look like an obvious cancer and you will go ahead and have surgery but some will just be in the grey area and so a needle test (FNA) is done. This is reported on a five point scale Thy 1-5 and again some people will be discharged with a diagnosis of a benign nodule whereas others will go straight to surgery. The majority of patients, however, will have a diagnosis of Thy 3a or Thy 3f which means that some cells have been seen that do not look normal but nor is there concrete evidence of a cancer. The risk of a cancer for these groups is 5-15% and 30% respectively and, although this is still low, we usually recommend a hemithyroidectomy to make a diagnosis. This does mean, however, that up to 85% of our patients that we operate on will turn out to have benign disease and, with hindsight, did not need surgery.
This is where molecular testing comes in. After the needle test, as well as looking at the cells under the microscope some is analysed to look at its RNA and DNA and identify genes that are known to cause cancer. The main 4, in increasing order of aggressiveness are:
If any of these come back then we would go ahead and recommend surgery. The company that I have been talking with is called Thyroseq and they produced reports like the ones below.
The really amazing thing is that with the specificity and sensitivity of the tests - if a test comes back as negative then there is a 97% chance of this being a true negative and so surgery would probably not be recommended as long as there were no other patient risk factor. If the test comes back as positive then we would go ahead with surgery. Following results from a multicentre trial - it seems as if up to 60% of patients with indeterminate nodules will have a negative report and can therefore avoid surgery with the consequent risks and anxiety associated with it.
This has been available in the US for some time now and I am excited to see it in the UK, it is truly the future of diagnosis for thyroid nodular disease.