With the continuous improvement in the performance of ultrasound instruments, the resolution is getting better and better, together with the application of new technologies such as puncture biopsy and ultrasonography, the awareness of people for medical checkups is increasing, the number of health checkups is increasing, and more and more thyroid diseases are detected. In particular, thyroid tumors and some specific inflammatory diseases are getting more and more attention and attention from the medical community and the people. The incidence of thyroid tumors is about 5% in the natural population when palpation is used, but about 30% to 65% when modern high-grade ultrasonic instruments are used. Palpation (commonly known as touching with the hand) can detect tumors over 1 cm relatively reliably, while ultrasound can detect many millimeter-level tumors that are negative to palpation.
Overall, benign tumors account for the majority of thyroid tumors, but due to overexposure to radiation, increased iodine intake, genetic factors, etc., malignant tumors of the thyroid gland, commonly referred to as cancer, are also on the rise, with a statistical incidence of thyroid cancer of about 1 in 10,000 or 10 per 100,000.
Although open surgery can treat almost all thyroid nodules, minimally invasive methods have become a hot research trend in the field of thyroid surgery. However, this approach does not free the patient from anxiety and concern about the true nature of the nodule, and the patient often has a significant sense of passive waiting and insecurity.
Others believe that although the vast majority of thyroid nodules are benign, there is a potential risk of malignancy, especially in benign nodules where there is focal suspicion of malignant tissue, and that surgical intervention should be performed, but once the nodules are pathologically confirmed to be nonmalignant after surgery, there is no shortage of complaints when patients face sequelae such as skin scars on the neck or hoarseness or even lifelong medication. Therefore, it is clear that research and development of treatments that are efficacious, quick, minimally invasive and less likely to cause complications could help to resolve this controversy.
Another type of endoscopic excision of thyroid tumors has brought cosmetic results for many patients while treating the disease well, as the incision is small and not in the neck, so there is no trace of skin on the neck after the procedure. However, endoscopic trauma cannot be ignored and many surgeons realize that this procedure cannot yet be called minimally invasive.
Ultrasound-guided percutaneous interstitial injection of anhydrous ethanol was once an important minimally invasive tool for the treatment of thyroid nodules, with good efficacy in small nodules and simple cystic nodules; however, because the dispersion of ethanol is affected by the internal fiber separation and tissue density of thyroid nodules, there are often defects of uneven dispersion and inconsistent sclerosis in larger nodules and nodules with more complex internal physical properties; In addition, the flow direction of ethanol is poorly controlled, and it is easy to leak around the nodules, leading to chemical adhesions. With the introduction and rise of microwave, radiofrequency, laser and other thermal ablation means, anhydrous ethanol chemical ablation treatment is now in decline.
High-energy laser ablation of thyroid nodules is a new type of treatment with clear efficacy and mild trauma, but it cannot be performed normally in China due to the licensing of the corresponding equipment. Nowadays, people are no longer strangers to microwaves, as almost every household has a microwave oven. Microwave ovens are self-evidently useful for heating up and cooking food. When microwaves are propagated in items rich in moisture, microwave energy can be converted into heat energy, and this heat energy occurs from inside the object, so it is also called endogenous heat, which is different from heating with a stove fire, which is called exogenous heat, and the food is heated up by heat conduction, which is not only thermally inefficient, but also the surface of the item is easily scorched.
The characteristic of microwave heat generation is skillfully applied to the treatment of tumors, and is more maturely used in the microwave ablation of liver tumors, kidney tumors, uterine fibroids and other diseases. Because the treatment process is combined with ultrasound, CT, MRI and other imaging methods, the treatment instrument is made into a very thin puncture needle, and there is a hot spot at the tip of the needle to enter the tumor to generate heat quickly and coagulate the dead tumor. Therefore, the treatment is very precise, slightly traumatic, and thoroughly effective.
After more than 10 years of clinical application of microwave ablation for liver tumors, Zhang Jianquan, director of Shanghai Long March Hospital, took the lead in developing radiofrequency and microwave ablation for thyroid tumors in China in 2005, and has treated nearly 1000 cases of benign thyroid tumors, recurrence of thyroid cancer after surgery and recurrence of lymph nodes in the neck. In addition, the department is actively carrying out multi-center clinical research on radiofrequency and microwave ablation of thyroid tumors in many hospitals in China, and conducting regular academic exchanges with foreign counterparts in Korea and Italy.
In 2010, we had the honor to invite Prof. Zhang to visit our department and provide microwave ablation treatment for many patients with thyroid tumors, and we witnessed his bold and skillful skills. After that, we concluded while treating and have performed microwave ablation treatment of thyroid nodules for dozens of patients, all of whom achieved technical success without complications, so that thyroid patients in Wuhan area also have the opportunity to enjoy the minimally invasive treatment of percutaneous ablation without neck scars.
The microwave thermal ablation treatment process is safe and controllable, with uncomplicated operational procedures and almost no complications. After a maximum follow-up of 6 years, it was confirmed that all nodules underwent complete coagulation and necrosis with 100% efficiency, and the ablated necrotic nodules that remained in the body had no negative impact on the patients, showing that ultrasound-guided percutaneous radiofrequency and microwave ablation of thyroid nodules have a good clinical application prospect.
This method can treat many types of thyroid tumors, including thyroid cancer. It is particularly effective for small (≤2 cm in diameter) substantial nodules, and for high-functioning nodules, it can also normalize thyroid function and the suppressed iodine uptake of extra-nodular thyroid tissue, and significantly improve the clinical symptoms of hyperfunction. Ultrasound-guided radiofrequency or microwave ablation for thyroid nodules is a good supplement to traditional open surgery and deserves further clinical promotion because of its low trauma, high accuracy, controllability, few complications and remarkable efficacy.
At present, the following types of thyroid diseases have been confirmed to be suitable for thermal ablation treatment.
I. Benign nodules: thyroid adenoma, nodular goiter, colloid thyroid retention (also known as cysts)
II. Malignant nodules: thyroid cancer, recurrent thyroid cancer, metastatic or recurrent cancer of the lymph nodes in the neck
However, the following cases have not been included in the scope of thermal ablation treatment.
I. Hyperthyroidism in adolescence
Iodine hyperthyroidism
Inflammatory thyroid conditions (subacute thyroiditis, Hashimoto’s disease easily accompanied by hypothyroidism), unless the tumor occurs in the context of Hashimoto’s disease
So, what kind of thyroid nodules require thermal ablation therapy? It should be emphasized that thyroid thermal ablation therapy is a technological innovation and a conceptual transformation in the field of surgical treatment, which is a very important complement to surgical treatment. Therefore, the choice of thermal ablation therapy is based on the premise that the patient’s condition requires surgical intervention. On this basis, those lesions that are too small to be touched by the surgeon, those lesions that are too diffusely distributed to be removed one by one by surgery, and those new lesions that occur as a result of scar adhesions in the neck due to previous surgical procedures are the best indications for choosing ultrasound-guided percutaneous thermal ablation therapy.
Thermal ablation of thyroid disease is a reliable and preferred option from the perspectives of minimally invasive, cosmetic, safety and effectiveness. As for whether to choose microwave ablation or radiofrequency ablation, the interventional physician will make a comprehensive study based on the size and location of the lesion.