This a good question and there are many factors that need to be considered. A doctor who specialises in thyroid RFA will take a detailed history, perform an ultrasound examination and sample the nodule(s) being treated to come to a decision. The final decision regarding suitability depends on a detailed conversation between patient and doctor. Patients should always weigh the risks and benefits of any procedure and also consider the alternative management options.
First of all, it is perhaps easier to say who is not suitable for RFA.
Patients likely to be unsuitable for thyroid RFA
- Patients with a diagnosis of thyroid cancer are not currently routinely treated using this technique, certainly in the UK (Please see the section on “future directions for minimal access thyroid treatments” for a more detailed discussion on thyroid RFA and cancer treatment). NICE approved thyroid RFA is for benign (non-cancerous) disease only.
- Patients who have very large nodules and especially those with several nodules on both sides of the gland (sometimes called a diffuse multi-nodular goitre) are less likely to benefit from thyroid RFA. These patients are at a much higher risk of poor nodule shrinkage, repeat treatment(s) and early nodule regrowth.
- Patients may have a confirmed benign thyroid nodule which is of a suitable size for treatment but still be unsuitable if there are no or only very mild nodule related local symptoms or cosmetic issues. Thyroid RFA should not be undertaken for nodules that do not cause either local symptoms or cosmetic issues. In this situation the risks of treatment are likely to outweigh the benefits of nodule shrinkage. These patients are better advised to leave the nodule alone if the nodule is confidently benign and reassessed if the nodule becomes a concern in the future.
- Finally there are several other factors for patients to consider before opting for RFA over surgery and these are discussed in the section on the limitations of thyroid RFA. Patients should clearly understand and accept the limitations of RFA before undergoing the procedure.
So who might be suitable for thyroid RFA?
- The most important criteria for suitability is to ensure that the nodule being treated is benign (non-cancerous). This assessment is made normally in three ways:
- The nodule is not behaving in a suspicious way (for example not growing rapidly)
- The nodule has a benign appearance on ultrasound assessment and there are no related suspicious features such as raised lymph glands in the neck.
- The nodule, on needle testing, returns a benign result. This requires an ultrasound guided fine needle aspiration test and is normally performed on one or two occasions depending on the appearance of the nodule.
- A second factor is the size of the nodule(s). There is no strict upper limit for nodule size but for larger nodules (those with a volume of more than 30 ml) patients should always be consented for the risk of more modest shrinkage, the need for further treatment and a risk of earlier regrowth. This being said, much larger nodules can and are treated with good outcomes with only a single treatment. Size alone is not the only factor as some larger nodules which contain fluid (cystic) areas as well solid tissue will still shrink well following RFA. A much more challenging type of thyroid disease to treat with RFA is a diffuse multi-nodular goitre, where several nodules are causing thyroid enlargement. Patients with this type of disease are poor candidates for RFA. Please see the section on “future directions for minimal access thyroid treatments” for a more detailed discussion on possible non-surgical options for patients with much larger nodules or multi-nodular thyroid disease.
- A reasonable assessment should be made that the nodule being treated is the cause for the patients symptoms. For example are local symptoms on the same side as the nodule? Are there any other identifiable causes for shortness of breath, an uncomfortable sensation on swallowing or cough?
- A further indication for RFA might also be nodules that are “hot” or “active”. These nodules are called autonomously functioning thyroid nodules (AFTN). The nodules produce excessive thyroid hormone and can cause wide ranging symptoms of thyroid over activity (hyperthyroidism) including anxiety, sweats, tremors, palpitations, tiredness and weight loss. Sometimes hot nodules may cause no symptoms at all but they are diagnosed on the basis of a thyroid function blood test, ultrasound scan and a thyroid uptake scan (also called a radio-isotope scan). These “silent” nodules still require treatment due to their long term effects including reduction in bone density and effects on the heart. RFA might be suitable in highly selected patients with small hot nodules as a second line option when they are unwilling or unable to undergo the more well established and recognised treatment options (including radio-active iodine therapy and surgery)
