Thyroid nodules are benign (non‑malignant) masses found in many patients and may sometimes require treatment. As an alternative to conventional surgical methods, Radiofrequency Ablation (RFA) or Microwave Ablation (MWA) methods have emerged.
Recent studies in this field have increased the efficacy and safety of MWA or RFA. In particular, researchers have developed comprehensive guides on how this method can be applied in the diagnosis and treatment processes. These developments offer promising results for patients with thyroid nodules.
Prof. Dr. Özgür KILIÇKESMEZ
Interventional Radiology / Interventional Neuroradiology
Differences Between Radiofrequency and Microwave
Both are similar cooled methods that convert energy into heat. The tips of the needles used deliver thermal injury to the nodule during ultrasound imaging, and energy is discontinued in normal tissues. Unlike radiofrequency, a grounding pad is present.
The burning process with radiofrequency takes longer. With microwave, the burning process is applied in a shorter time. Especially for nodules larger than 2 cm, choosing the microwave method makes the procedure more comfortable. The microwave method is approximately 10-15% more expensive compared to radiofrequency.
Indications for MWA or RFA in Benign Thyroid Nodules
Radiofrequency ablation is a treatment method preferred in certain cases for benign thyroid nodules. This treatment is applied depending on various factors such as the size or location of the nodule. The symptoms experienced by patients and cosmetic concerns play an important role in whether the treatment is applied.
MWA or RFA is especially preferred in the treatment of symptomatic nodules because these symptoms can adversely affect patients’ daily lives. The indications for MWA or RFA in symptomatic thyroid nodules are:
- Pain or discomfort originating from the nodule.
- Difficulty swallowing such as dysphagia or the sensation of a foreign body.
- Nodules of a visible size that cause aesthetic concerns in the neck region.
This treatment method varies according to the size and location of the nodule. In patients with a small neck circumference, MWA or RFA can be applied at an earlier stage due to cosmetic concerns. In addition, there is a direct relationship between the size of the nodule and the severity of the symptoms. As the severity of the symptoms increases, the need for MWA or RFA also increases.
Microwave or Radiofrequency ablation is indicated according to the following criteria:
- Continuous growth observed in large nodules (2 cm and above).
- Nodules without intense calcification.
The applicability of MWA or RFA is also determined by the ultrasound characteristics of the nodule and the results of the biopsy performed. In nodules confirmed to be benign by prior fine needle aspiration or core needle biopsy, repeated biopsy is generally not necessary. This treatment option should be planned according to the location of the nodule and its relationship with the surrounding tissues.
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Use of MWA or RFA in Recurrent Thyroid Cancers
In recurrent thyroid cancers, Microwave or Radiofrequency ablation (MWA or RFA) is an effective method, especially in situations where surgical options are limited. This method can be used as an alternative to surgery or for curative and palliative purposes.
It was first used in eight patients in 2001. This application has been supported by various studies and two meta‑analyses. Recent research shows that MWA or RFA provides successful results in patients who require surgery but carry high surgical risks.
The indications determined for MWA or RFA are as follows:
- Patients with high surgical risk.
- Complications resulting from previous surgical operations.
- Individuals with poor lung function or serious cardiovascular diseases.
- Patients unsuitable for surgery due to old age.
MWA or RFA should be applied when complete radiological ablation of the tumor is possible. At the same time, there should be no metastasis beyond the neck. When performed with curative intent, it is recommended for cases where the number of recurrent tumors is less than three or four and the largest tumor diameter is less than 1.5-2 cm.
MWA or RFA may also be preferred to reduce symptoms and improve quality of life. This method can successfully manage recurrent tumors generally without significant complications.
MWA or RFA in Primary Thyroid Cancers
While primary thyroid cancers are usually treated surgically, in some cases MWA or RFA may be considered as an alternative method. Especially for patients unsuitable for surgery, MWA or RFA has become an important option.
Trials in patients with papillary thyroid microcarcinoma have shown that MWA or RFA provides effective local ablation. The results of these studies offer positive findings both in the short term and after a four‑year follow‑up period.
Thermal Ablation Methods:
- Radiofrequency Ablation (RFA)
- Laser Ablation (LA)
- Microwave Ablation
In advanced thyroid cancers, RFA and LA have been used as palliative treatment methods. In anaplastic or advanced medullary thyroid cancers, these methods have reduced compressive symptoms in some patients. However, there is no consensus on the clinical efficacy of thermal ablation in anaplastic and medullary cancers. This suggests that the effect of the method on these types of cancers may be limited.
Use of MWA or RFA in Follicular Neoplasms
The approach of Microwave or Radiofrequency ablation in the treatment of follicular neoplasms has attracted significant attention in recent years. MWA or RFA is recommended as an alternative option, especially for patients who are not suitable for surgical intervention.
Research has shown that MWA or RFA is reliable and effective in benign thyroid nodules. However, when it comes to follicular neoplasms, there are limitations and precautions regarding its use:
- Size of the neoplasm: MWA or RFA is suitable for lesions smaller than 2 cm.
- Bethesda classification: Lesions graded as Bethesda‑3 or Bethesda‑4 may carry risk.
These situations indicate that MWA or RFA carries potential risks for follicular neoplasms and should be used with caution, especially in cases with a risk of malignancy. Further research and clinical experience will determine the safety and efficacy of this treatment method. Therefore, a comprehensive evaluation before treatment is mandatory. The use of MWA or RFA should be assessed based on certain criteria and each patient’s condition should be considered individually.
Pre‑Procedure Evaluations for MWA or RFA
Before choosing the option of Microwave or Radiofrequency ablation in the treatment of thyroid nodules and recurrent thyroid cancers, a careful evaluation is mandatory. In this process, various laboratory and imaging tests are required to accurately determine the patient’s condition. First, for thyroid nodules, the structure of the nodules and the surrounding anatomical structures are examined in detail using ultrasound (US). During this examination, the following features are evaluated:
- Nodule size,
- Echogenicity,
- Solid component ratio,
- Internal vascularity,
Laboratory tests include:
- Complete blood count,
- Coagulation tests (bleeding time, prothrombin time, activated partial thromboplastin time),
- Thyroid function tests (TSH, T3, fT4),
In the case of recurrent thyroid cancer, additionally:
- Serum TSH,
- Thyroglobulin (Tg),
- Anti‑Tg antibody levels
should be measured. These tests can indirectly indicate the success of the MWA or RFA procedure. In terms of imaging, neck CT and MRI examinations can be used to detect the spread of the nodules and additional lesions. These evaluations clarify the patient’s pre‑treatment status and provide important data for post‑MWA or RFA follow‑up.
Use of Anticoagulant and Antiplatelet Medications
Before the MWA or RFA procedure, patients with a risk of bleeding must be carefully evaluated. Patients undergoing anticoagulation therapy, especially those using drugs such as aspirin and clopidogrel, are advised to stop these medications for a certain period before the procedure. The discontinuation periods for the relevant drugs are as follows:
- Aspirin or clopidogrel: 5 days
- Warfarin: 3-5 days
- Heparin: 4-6 hours
The timing of medication use after the procedure should be adjusted as follows:
- Heparin: 2-6 hours after MWA or RFA
- Warfarin: the night following MWA or RFA
- Aspirin or clopidogrel: the day after MWA or RFA
Doctors should plan the discontinuation of anticoagulant and antiplatelet therapy based on the patient’s general health status and the specifics of the procedure. In cases where platelet aggregation inhibitors are discontinued, a cardiologist’s consultation should be obtained and patient preferences considered. If necessary, a switch to short‑half‑life heparin may be made.
Techniques for MWA or RFA in Benign Thyroid Nodules
In the treatment of benign thyroid nodules, Microwave or Radiofrequency ablation presents a minimally invasive approach. This method is especially ideal for patients who are not suitable for or do not desire surgical intervention.
In MWA or RFA procedures performed under local anesthesia, perithyroidal lidocaine injection is preferred for pain control. This technique prioritizes the patient’s comfort. During the procedure, an adequate amount of lidocaine is applied to the skin and thyroid capsule to reduce pain. Additionally, the techniques used during MWA or RFA include:
- Trans‑isthmic approach: The RF electrode is positioned through the thyroid isthmus.
- Moving‑shot technique: The electrode is drawn from the deepest part of the nodule toward the surface.
These techniques provide effective and safe treatment during ablation. Recently, vascular ablation techniques have also been developed as an adjunct to this method. These new approaches aim to minimize marginal regrowth in nodules.
Throughout the procedure, the RF electrode is monitored in real‑time under ultrasound guidance, minimizing the risk of thermal injury. The absence of general anesthesia or sedation facilitates early detection of possible complications and increases patient safety during the procedure.
Technique Selection in Recurrent Cancers for MWA or RFA
In the treatment of recurrent thyroid cancers, the MWA or RFA method has gained importance, especially due to the challenges that arise after surgery. In this technique, a careful procedure is applied with emphasis on preserving the surrounding tissues.
The choice of electrode tip is made according to the size and location of the tumor. Smaller electrode tips are ideal for tumors in sensitive areas. With this method, recurrent cancer tissues are safely ablated.
Standard techniques include:
- Perilesional lidocaine injection
- Hydrodissection technique
- Moving‑shot technique
The hydrodissection technique creates a buffer zone between the tumor and vital structures, thereby protecting these structures during ablation. A 5% dextrose solution is preferred as the fluid used since it prevents electrical conduction. Cold dextrose is continuously injected, thereby preventing thermal spread. Each technique is carefully chosen based on the tumor’s location and surrounding risks, thereby reducing the risk of complications after ablation.
Clinical Follow‑ups After MWA or RFA
In the post‑MWA or RFA period, the recommended follow‑up process for the management of non‑functioning benign thyroid nodules includes the following steps. First, immediately after nodule ablation, the entire nodule should temporarily appear hyperechoic on ultrasound.
Then, grayscale and color Doppler ultrasound should be used to evaluate whether ablation has been completed. These two methods are important for detecting whether the remaining nodule tissue is vascularized. If viable nodule parts are detected, additional ablation may be necessary due to the potential for regrowth.
The following aspects are considered in post‑MWA or RFA evaluations:
- Symptom score related to the nodule: symptoms such as neck pain, dysphagia, foreign body sensation, discomfort, and cough are evaluated by both the patient and the physician.
- Cosmetic score: Changes in the patient’s appearance are recorded by the physician.
Finally, the percentage of volume reduction is calculated by the ratio of the difference between the initial and final volumes to the initial volume. This calculation serves as an objective indicator of the effectiveness of MWA or RFA.
Follow‑up After AFTN (Toxic Nodule) Treatment with MWA or RFA
After the treatment of autonomously functioning thyroid nodules (AFTN) with MWA or RFA, a detailed follow‑up plan is mandatory to evaluate the success of the application. Monitoring requires an approach customized to the patient’s condition. First, thyroid function tests must be carefully performed at each control after the procedure. These tests include measurements of TSH, T3, and fT4. Additionally, thyroid antibody levels should be measured:
- Anti‑TPOAb and anti‑TGAb levels, which are indicators of changes in thyroid function.
- Based on hormonal changes, adjustments in the dosage of antithyroid drugs may be made. This is examined under three different categories:
- Remission: Thyrotoxicosis after discontinuation of antithyroid drugs
- Improvement: Thyrotoxicosis with a reduced drug dose
- No response: No change in drug dosage
Imaging methods are also critical. Ultrasound (US) examination should be performed at every control, and changes in the nodule’s size, volume, intranodular vascularity, and echogenicity should be evaluated. In addition, thyroid scintigraphy is helpful in classifying thyroid nodules:
- Type 1: Hot nodule
- Type 2: Nodule uptake similar to extrathyroidal tissue
- Type 3: Cold nodule or non‑visualized nodule
If thyroid functions or symptoms do not completely resolve, repeated MWA or RFA or alternative treatments should be considered. The treatment process should be carefully adjusted according to the patient’s response.
Follow‑up of Cervical Thyroid Cancer Recurrence
After MWA or RFA, specific protocols are applied to monitor the recurrence of cervical thyroid cancer. These protocols include clinical, laboratory, and imaging techniques to best assess the patient’s condition. First, the tumor’s volume, maximum diameter, and vascularity are evaluated using ultrasound. In addition, the presence of new metastatic tumors is examined.
- Tumor volume and maximum diameter
- Vascularity
- Presence of new metastatic tumors
Among laboratory tests, serum Tg level and anti‑Tg antibody measurements are important. These measurements indicate the effectiveness of the ablation and a possible immune response.
- Serum Tg level
- Anti‑Tg antibody
In terms of imaging, a contrast‑enhanced CT scan is recommended. This determines the presence of any viable residual tumor or new tumor development. If recurrence is detected on ultrasound or CT, additional ablation treatments can be planned. After a successful ablation, the contrast enhancement of the tumor decreases or disappears. These processes are critically important for optimizing treatment outcomes.
Follow‑up Protocols in Primary Thyroid Cancer
Follow‑up processes after MWA or RFA in primary thyroid cancer treatment have a significant impact on patients’ health. A prospective study has outlined the timeline for follow‑up after MWA or RFA:
- First month,
- Third month,
- Sixth month,
- Twelfth month.
At these time intervals, patients’ conditions are evaluated using ultrasound and contrast‑enhanced ultrasound. Performing a core needle biopsy (CNB) at the third month is critical to check the effectiveness of the procedure. The findings support that ultrasound follow‑ups should continue annually after the procedure. In addition, a careful evaluation should be made to detect any new pathological changes in the thyroid gland and surrounding lymph nodes:
- Metachronous development of PTC,
- New lymph node metastases.
These situations can be further examined in detail with the aid of CT. If the lesions do not grow or change in size after MWA or RFA, it is recommended that these lesions be further evaluated with CNB or FNA. These protocols are essential to ensure the optimal management of the patients’ health.
Suitability of Benign Thyroid Nodules for MWA or RFA
Microwave or Radiofrequency ablation (RFA) is recommended as an effective treatment method particularly in certain types of benign thyroid nodules. Suitability for treatment is determined by the structural characteristics of the nodule.
MWA or RFA is considered a first‑line treatment in solid and predominantly solid thyroid nodules. These nodules are generally non‑functional, and the treatment outcomes are quite successful. The efficacy of MWA or RFA is measured by improvements in nodule volume, as well as symptomatic and cosmetic scores.
In addition, MWA or RFA is recommended for:
- Cystic nodules with a solid component,
- Completely solid thyroid nodules,
- Non‑functional thyroid nodules.
Nodule composition and suitability for treatment are classified according to the following features:
- Cystic nodules: MWA or RFA is recommended as an alternative treatment if ethanol ablation (EA) fails to resolve symptoms or in cases of recurrence. A large cystic component suggests that EA may be more appropriate.
- Predominantly cystic thyroid nodules: In these nodules, the cystic component varies between 50-90%. While EA is recommended as the first‑line treatment, MWA or RFA may be suggested in cases of recurrence or failure to completely resolve symptoms.
- Solid nodules: MWA or RFA is an effective first‑line treatment method for this nodule type. It achieves successful volume reduction and generally requires few treatment sessions.
Sufficiency of a Single‑Session MWA or RFA Treatment
Microwave or Radiofrequency ablation for thyroid nodules provides successful outcomes in many patients. However, in some cases a single treatment session may be insufficient. Particularly in large nodules or when symptoms are not completely alleviated, additional treatment sessions may be required. Long‑term follow‑ups have shown that in cases where the nodule volume is greater than 20 mL, a single session is generally insufficient.
The main indications for recommending additional treatment are:
- Incomplete alleviation of symptoms after treatment,
- A volume reduction rate (VRR) of less than 50%,
- Regrowth of the tumor.
Although uncertainties remain regarding the timing and necessity of additional treatment, careful post‑ablation monitoring is recommended. Monitoring the growth of the viable portions of the nodule may be critical in determining whether the patient will require further treatment.
Efficacy of MWA or RFA in OTN Treatment
Microwave or Radiofrequency ablation is an important non‑surgical method used in the treatment of OTN. This technique achieves a significant reduction in the volume of thyroid nodules. The effects of MWA or RFA have been comprehensively examined, and the results demonstrate the success of the treatment.
- Nodule volume: After MWA or RFA, volume reductions of 36.4-51% at 1 month, 69-74.5% at 6 months, and 75% at 12 months were achieved.
- Neck discomfort and cosmetic issues: Along with the volume reduction, improvements in neck discomfort and appearance were observed.
The impact of MWA or RFA on thyroid functions is also noteworthy. After the treatment, the use of antithyroid drugs was reduced or discontinued in most patients. Serum TSH levels returned to normal in most patients post‑procedure.
- Antithyroid drug use: Post‑treatment, 21.7-50% of patients discontinued medication.
- Serum TSH levels: Post‑procedure, 55.6-81.8% of patients returned to normal TSH levels.
These data demonstrate that MWA or RFA is an effective non‑surgical alternative in the management of OTN. Patient satisfaction is high and complication rates are reported to be low. In summary, MWA or RFA emerges as a safe and effective method to control thyroid nodules and thyrotoxic symptoms.
The Role of MWA or RFA in Recurrent Thyroid Cancer
In the treatment of recurrent thyroid cancer, radiofrequency ablation has gained importance as a non‑surgical method. Initiated studies have revealed the potential of MWA or RFA in this field.
Two meta‑analyses have shown that MWA or RFA significantly reduces tumor size and serum Tg levels in local recurrences. In one study, a large portion of tumors completely disappeared after MWA or RFA. The findings from these studies are as follows:
- Tumor volume reduction rate: 50.9–98.4%
- Complete disappearance rate: 68.8%
- Recurrence rate in the treated area: 0%
MWA or RFA offers higher success rates when the tumor size and number are limited. Research by Kim and colleagues indicated that the long‑term outcomes of recurrent tumors treated with MWA or RFA are equivalent to surgery. Additionally, the analysis showed that MWA or RFA required fewer treatment sessions compared to alternative therapies and that recurrence rates were low. Relevant findings include:
- Number of tumors treated: up to three per patient
- Tumor diameter: less than 2 cm
- Long‑term recurrence rates: no difference between MWA or RFA and surgery
Furthermore, in one study, more than half of the patients who underwent MWA or RFA experienced symptom improvement within six months after treatment. However, in technically challenging cases, the failure rate of MWA or RFA may increase. Such cases are generally due to complications such as severe calcification or the tumor’s proximity to large vessels. In such situations, repeated MWA or RFA sessions may be required.
Effects of MWA or RFA in Primary Thyroid Cancer
Microwave or Radiofrequency ablation has shown promising results in the treatment of primary thyroid cancer. A prospective study demonstrated that this treatment achieves a significant volume reduction in the short term:
- 53% reduction in volume in the first month,
- 81% reduction in the third month,
- 92% reduction in the sixth month,
- 96% reduction in the twelfth month,
- 100% reduction in the eighteenth month.
Long‑term results have similarly been successful, with an average volume reduction of 98.5% reported at four years. During this period, no local tumor recurrence or metastatic lesions were observed.
However, small cancers detected after surgery and microscopic metastases indicate that the capacity of MWA or RFA to control regional disease may be limited. These findings suggest that while MWA or RFA can be effective in some cases, further research is needed regarding the scope of the treatment.
Safety and Side Effects of MWA or RFA
This procedure offers effective results for both benign nodules and recurrent thyroid cancers. When performed by experienced operators, MWA or RFA is safe and well‑tolerated with low complication rates.
The complications encountered during and after the procedure are generally mild and manageable. In this context, the safety and tolerability profile of MWA or RFA has been examined under the following headings:
Major Complications:
- Recurrent laryngeal nerve injury
- Vagus nerve injury
- Horner’s syndrome
- Spinal accessory nerve injury
- Brachial plexus injury
- Nodule rupture
- Thermal injury of the esophagus by the thyroid gland
Minor Complications:
- Hematoma
- Nausea
- Skin burn
- Transient thyrotoxicosis
- Lidocaine toxicity
- Hypertension
- Pain
Complications rarely become severe and are usually resolved with compression or simple treatments. Voice changes are the most frequently encountered major complication; however, this condition is not permanent and is generally transient.
To reduce the risk of voice changes, the trans‑isthmic approach and moving‑shot technique are used. Special care must be taken during the procedure by considering the anatomical variations of the vagus nerve and recurrent laryngeal nerve. To prevent nerve injuries, a careful procedure under ultrasound guidance is essential.
Thyroid nodule rupture manifests as sudden neck swelling and pain after the procedure. This situation is generally managed conservatively; however, if abscess formation occurs, surgical intervention may be required.
The management of hematomas is performed with simple compression, and most resolve spontaneously within a few weeks. During electrode placement, thyroid arteries are carefully examined using Doppler ultrasound, thereby minimizing the risk of significant bleeding.
Post‑MWA or RFA hypothyroidism is rarely seen and generally occurs in patients who already have thyroid dysfunction or elevated anti‑TPOAb. Transient hyperthyroidism may be observed as a result of the treatment; however, this condition is generally asymptomatic and returns to normal within a few weeks. Pain during MWA or RFA is the most common minor complication and is usually managed with appropriate adjustments during the procedure.
In conclusion, MWA or RFA is considered a safe and well‑tolerated treatment method for thyroid nodules. Its low complication rates and effective management techniques make this procedure an important option in thyroid nodule treatment.
Thyroid Ablation Prices 2025
The cost of thyroid ablation treatment depends on various factors. Firstly, the type of treatment is an important factor affecting the cost. In addition, the location of the selected hospital or clinic also plays a role in pricing. Moreover, the experience and level of expertise of the doctor may also be decisive in the fee. In private hospitals, the cost of this treatment is generally higher. As a result, the price of thyroid ablation treatment varies from hospital to hospital and according to the treatment method applied (RF / Microwave).
Frequently Asked Questions
Yes, ablation treatment can be applied to toxic nodules. Even if there are many nodules, this does not hinder the effectiveness of the treatment. Especially in cases of hyperthyroidism, the aim is to reduce the nodules in the thyroid gland that produce excess hormones. This method can be considered as an alternative to drug therapy or surgery. The patient’s overall health status and the characteristics of the nodules are among the determining factors in planning the treatment. Therefore, laser ablation may be recommended by the physician based on the patient’s condition.
The patient is not put under anesthesia during ablation; if a surgical intervention is involved, the patient may be put under anesthesia. In non‑surgical cases, the use of sedative medications is sufficient. Therefore, whether the patient is put under anesthesia depends on the nature of the procedure.
Yes, the ablated tissue remains as dead tissue in a reduced size. In about 5% of cases, regrowth may occur, but these never reach their original size.
Additional Resources and Documents
Prof. Dr. Özgür Kılıçkesmez graduated from Cerrahpaşa Medical Faculty in 1997. He completed his specialization at Istanbul Education and Research Hospital. He received training in interventional radiology and oncology in London. He founded the interventional radiology department at Istanbul Çam and Sakura City Hospital and became a professor in 2020. He holds many international awards and certificates, has over 150 scientific publications, and has been cited more than 1500 times. He is currently working at Medicana Ataköy Hospital.
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