The great problem with follicular thyroid cancer is that it is unusual to be able to confirm that the lesion is malignant untilthe capsule surrounding the lesion is fully examined by the pathologist. Intra-operative frozen section (rapid assessment by the pathologistof the specimen)is stated in the 2007 guidelines to be unhelpful.Some pathologists feel that the paraffin section assessment of the capsule may be jeopardised by frozen section but this is not entirely our view.
If itis certain that the lesion is malignant, then total thyroidectomy is mandatory. In most cases one may not know for three or four days after surgery the exact nature of the lesion. Lack of evidence of malignancy at this stage must be viewed with great scepticism. One may be helped if the lesion is known to be associated with thyroid overactivity (hot nodule on nuclear scan). Hot nodules are almost invariably non-malignant. The surgeon should discuss pre-operatively the options to the patient if there is any doubt in the diagnosis.
The options are:
This has the advantagethat ifthe lesion is cancer, no further surgery is necessary. The disadvantage of this approach is that in the case of a lesion that is finally shown to be non-malignant the patient will need to go on lifelong thyroxine, which may not have been necessary if limited surgery had been performed (lobectomy).
This has the advantage that in non-malignant lesions no more needs to be done. However, the down side of this approach is that in the case of cancer a second operation removing all thyroid tissue needs to be performed (completion thyroidectomy).
Guidelines for the management of follicular cancer in the UK have been published in 2007, and like papillary cancer, follicular cancer should be managed by an expertthyroid cancer physician with help from a multidisplinary team (MDT).
The Guidelines for Follicular Cancer Treatment aresummarised below:
1#. Follicular carcinoma under 1cm with minimal capsular invasion should be treated by thyroid lobectomy alone.
2#. Patients with follicular carcinoma with vascular invasion should be treated by total thyroidectomy.
3#. Patients with follicular carcinoma more than 4 cms in diameter should be treated by near-total or total thyroidectomy.
4#. Patients at low risk with tumours greater than 2 cms may be treated by lobectomy alone with thyroxine therapy for life, if the MDT agrees and there is fully informed consent.
5#. There are no guidelines for low risk tumours between 2 and 4 cms in diameter that show minimal invasion. The managementis left to the discretion of the MDT.