Thyroid No Surgery 101 What Are The Types of Thyroid Nodules Suitable For Thyroid Ablation?
- Detailed evaluation including biopsy and if needed molecular markers and classifier confirming benign nodule with very low risk for thyroid cancer.
- The evaluation should be done by a clinical thyroidologist with experience in endocrine neck ultrasound and be certified by AACE with the title of ECNU ( Endocrine certification in neck ultrasound.
- The first category for ablation therapy is a thyroid or parathyroid cyst.
- The cyst seen above is 90% fluid with a solid component.The biopsy should be aimed at the solid part and any area with Doppler blood flow.The presence of clear fluid should bring up the possibility of a parathyroid cyst. Elevated PTH in washout during the biopsy will make the diagnosis. 2 parathyroid cysts, and one thyroid cyst seen below.
- US guided needle inserted to draw out the fluid
- Tip of needle seen in the center of the cyst just prior to removing the fluid and replacing ethanol in the cavity.
- Medical Grade ethanol is injected in to the cyst cavity.
- Massive cyst
- After PEI
- The mural solid part has >90 degree edges to the cysts wall. This is benign. Acute angles to the cyst wall are more likely to be PTC. > 90 % decrease in size post PEI seen below.
- This mural solid area has acute angles to the capsule and 4+ Doppler blood flow. It was a PTC.
- Ethanol Ablation PEI is the first line treatment for cysts. If there is >50% solid radiofrequency ablation RFA or in combination with PEI can be used.
- Second is a mixed cyst solid benign thyroid nodule seen below.
- The cyst component is about 50%. The solid areas need careful biopsy especially in Doppler blood flow areas. Papillary thyroid cancer PTC is known to form cysts. Mutation studies can be helpful to decrease the odds of missing a PTC. PEI, or PEI/RFA can be used if the mixed cysts was benign with very very low chance of PTC.
- The third is a spongiform nodule seen below
- These nodules are 99-100% benign. They come in 3 degrees of micro-cystic components seen below.
- This type is rarely cancer and may not need a biopsy before the ablation.
- RFA is the treatment of choice over surgery.These tend to get the best shrinkage with therapy over compact soli
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- USA has no FDA approved ThyroidRF Mini-Probe system. The overnight trip to Europe for RFA can save you a surgery. Also, HIFU (high intensity focused ultrasound ) is available in Europe and Asia. This system is totally non-invasive as the ultrasound probe sits on the skin of the neck instead of the probe inside the nodule to be ablated.
- HIFU uses 2 Ultrasound beams to converge to cause heat.
Before and after HIFU
- The last nodule is the solid or compact.
- This type has the least shrinkage with RFA. The compact nature of the nodule makes ablation more difficult with the result of 30-50% decrease in size. The patient must be told this before the treatment. Also a careful biopsy and mutation studies are needed in these to decrease the risk of using RFA on a cancer.
- Generally solid nodules > 6 cm are less likely to have a good result with RFA. HIFU the nodules need to be even smaller to be successful.
- Microwave AblationMWA is the next thyroid ablation system.
- Microwave uses an antenna probe which has a large bore of #16 and is long. A thyroid antenna of shorter length and smaller size of at least #18. I will call this a ThyroidMW-Mini-Probe when we get one to use on thyroid nodules and cancer.