(Seoul = Yonhap News) Reporter Kim Gil-won = Thyroid cancer is often called a โgood cancerโ because it progresses slowly compared to other cancers and has good treatment results. Among them, 'low-risk papillary thyroid cancer', which is less than 1 cm in size and has no invasion of surrounding tissue or lymph node or distant metastasis, is often monitored through regular ultrasound examinations rather than undergoing surgery immediately upon discovery.
The idea is to consider the burden of surgery and the possibility of future progression rather than hastily removing it just because it is cancerous. However, there are also patients who do not want surgery but feel the burden of watching the cancer remain in their bodies.
However, in the future, it is expected that a third option will be available to treat small thyroid cancers smaller than 1 cm. In addition to surgery or observation, a path has been opened to select radiofrequency ablation (RFA), which involves inserting a thin electrode into the cancerous area and burning away the tumor with radiofrequency heat, as an official treatment.
According to the Korean Society of Thyroid Radiology and the Korean Thyroid Society on the 30th, the two societies have recently prepared the final draft of the 'Clinical practice guidelines for radiofrequency ablation for low-risk papillary thyroid cancer' containing these contents and are collecting member opinions ahead of the official announcement.
Papillary thyroid cancer, which accounts for the majority of thyroid cancers, gets its name from the fact that when viewed under a microscope, the cancer cells show a 'papillary' structure with finger-shaped protrusions. In general, the progression is slow and the prognosis is good, and in particular, many low-risk papillary thyroid microcarcinomas measuring less than 1 cm do not show significant changes over a long period of time.
For this reason, 'active surveillance', which regularly checks the size of the tumor and whether it has metastasized to the lymph nodes, has become the main treatment strategy for these small cancers, rather than performing surgery unconditionally.
The key point of this guideline is that heat treatment, which has the effect of local tumor removal through radiofrequency ablation, can be considered as a treatment method for patients with low-risk papillary thyroid cancer less than 1 cm.
The specific target set by the society is adult patients with low-risk papillary thyroid cancer whose size exceeds 0.5 cm but is less than 1 cm. Subjects were selected by comprehensively considering not only tumor characteristics and patient factors, but also the expertise of the operator and medical institution.
Until now, there were two choices for microscopic thyroid cancer less than 1 cm in size, โwhether to operate or wait and see.โ Now, a third option has been added, โwhether to remove it with high frequency.โ
Radiofrequency ablation is a treatment that inserts a thin electrode into cancer tissue while looking at ultrasound waves and generates heat with high-frequency current to kill the tumor. Unlike surgery to remove the thyroid gland, it is characterized by treating the cancerous area locally.
The suggestion of this treatment as a new option was supported by accumulated clinical evidence.
In a systematic literature review and meta-study published in the latest issue of the international journal 'Korean Journal of Radiology', a comprehensive analysis of 35 studies (9,787 tumors) related to low-risk papillary thyroid cancer showed that the rate of complete disappearance of tumors in imaging tests after radiofrequency ablation reached 87.2%, and the overall disease progression rate was calculated to be 1.3%.
However, not all thyroid cancers smaller than 1 cm are eligible for radiofrequency ablation.
The guidelines do not recommend radiofrequency ablation in cases of highly aggressive cytopathological subtypes, or in cases where the cancer has clearly invaded beyond the thyroid gland or has spread to cervical lymph nodes or other organs.
The experience of the operator and the expertise of the medical institution are also important conditions. This is because important structures such as the nerves that move the vocal cords, organs, and esophagus are concentrated around the thyroid gland.
Accordingly, the guidelines recommend that the procedure be performed by a doctor with sufficient expertise and experience in thyroid imaging, thyroid cancer treatment, biopsy, and radiofrequency ablation, and that the procedure be performed at a medical institution equipped with appropriate image guidance equipment and emergency response system.
Before the procedure, patients were required to undergo a detailed ultrasound examination by an experienced expert, and computed tomography (CT) was also recommended along with ultrasound to establish a treatment plan and evaluate lymph node metastasis. Vocal cord function and risk of bleeding and thromboembolism are also preliminary evaluation items.
Treatment does not end when the cancer is removed with high frequency. The guidelines call for thyroid and neck ultrasound to be performed at 1 to 3, 6, and 12 months after the procedure, and to be examined annually for at least 5 years thereafter. It is necessary to check not only whether cancer remains or grows again in the treated area, but also whether new papillary thyroid cancer, lymph node, or distant metastasis occurs.
Professor Seung-hoon Seung of the Department of Otolaryngology at Dankook University Hospital (Chairman of the Korean Society of Neuromonitoring) said, "For thyroid papillary cancer, even if it is less than 1 cm, the treatment strategy may vary depending on the location and nature of the cancer. From the patient's perspective, it is important to select a method that is suitable for the patient after being fully explained the pros and cons of surgery, active observation, and radiofrequency ablation, as well as the need for long-term follow-up, rather than making simple judgments such as 'It's small, so let's wait and see' or 'It's cancer, so let's get rid of it.'" said.
