Radiofrequency ablation (RFA) is showing efficacy as a potential noninvasive option for the treatment of low-risk microcarcinomas in papillary thyroid cancer (PTC) when measures beyond active surveillance are warranted, results of further review show.
“The results of the current study suggest that RFA may work as a useful alternative treatment strategy in which patients are treated minimally invasively with curative intentions,” the meta-analysis authors report. published online in JAMA Otorhinolaryngology – Head and neck surgery.
Commenting on the research, Joanna Klubo-Gwiezdzinska, MD, PhD, said the work offers useful evidence on the potential role of RFA in low-risk micro-PTC — with some notable caveats.
“I agree that RFA could be a good option for patients who are unwilling or unable to accept active surveillance and for patients who are at high surgical risk due to comorbid conditions,” he said. she declared. Medscape Medical News.
However, “ARF for patients with evidence of nodule growth requires more data to analyze and a longer follow-up period instead of the fact that 21% of nodules subjected to ARF did not disappear, out of based on the data provided by the authors,” noted Klubo-Gwiezdzinska, who is acting chief of thyroid tumors and functional thyroid disorders at the National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases (NIH-NIDDK ), in Bethesda, Maryland.
When active monitoring is not‘Enough
PTC microcarcinoma, defined as 10 mm or less, is very common, accounting for around half of all papillary thyroid cancers diagnosed in some countries, and outcomes for these cancers are excellent, with disease-specific survival of more than 99% after 10 years.
Guidelines in the United States and Europe generally recommend surgery (lobectomy) as the standard treatment for thyroid cancerhowever, with many low-risk microcarcinomas remaining indolent and never progressing to the point of requiring treatment during a person’s lifetime, some also recommend considering active surveillance, or watchful waiting, for these cancers at low risk.
In situations such as evidence of tumor growth during active surveillance, some countries, especially Asian countries, also suggest considering thermal ablation techniques, including RFA, as an alternative to surgery. , with key advantages including lower costs and potentially a lower risk of complications compared to surgical lobectomy.
Otherwise, RFA is more generally reserved for benign nodules, recurrent PTCs, or inoperable disease.
To investigate the outcomes reported with RFA specifically in the treatment of PTC microcarcinoma, the authors, led by Sam PJ van Dijk, BSc, of University Medical Center Rotterdam, The Netherlands, identified 15 studies published after 2016 involving 1770 adult patients and 1822 tumors that received RFA for the treatment of low-risk PTC microcarcinomas, defined as measuring 10 mm or less.
The studies were conducted in China and South Korea, where RFA is more commonly used in low-risk microcarcinoma CTP.
The patients were 77.9% women and had an average age of 45.4 years. The analysis excluded patients with preablation lymph nodes or distant metastases, disease recurrence, or extrathyroidal extension.
Of the 1822 tumors treated with RFA, 49 required additional RFA treatment and one tumor had two additional treatments.
With a mean follow-up of 33 months (range: 6-131 months), the primary outcome of the combined rate of complete disappearance of PTC microcarcinoma on ultrasound was 79%.
The overall rate of tumor progression was 1.5% (26 patients) and residual local PTC microcarcinoma occurred in 0.4% (7 tumors).
New PTC microcarcinoma occurred in 0.9% (15) of patients; 0.2% (4) developed lymph node metastases during follow-up, and no distant metastases were observed.
Minor complications occurred in 45 patients, and there were three major complications, including two voice changes that lasted longer than 2 months and one cardiac arrhythmia.
“This study suggests that radiofrequency ablation is a safe and effective method to treat certain low-risk papillary microcarcinomas of the thyroid,” van Dijk and colleagues say.
Questions regarding the 20% of patients who still had residual nodules
Although the analysis does not include direct comparisons between RFA and lobectomy, Klubo-Gwiezdzinska noted that in general, “RFA appears to be associated with a lower complication rate compared to surgery, but also with less efficacy, with 21% of patients presenting with residual nodules.”
The results raise the question of whether “all residual lesions are associated with persistent disease and, if so, do they warrant further intervention?” she added.
At this point, the authors note that only 7 (0.4%) of 21% of patients with persistent nodules had residual microcarcinoma PTC cells after RFA, a fact that underscores that “evaluation of tumor response in patients with mPTC after RFA is complicated”. ,” they write.
One of the main concerns regarding the assessment of responses in the RFA is that fine needle aspiration has been shown to reduce diagnostic accuracy after treatment due to insufficient cellularity in the ablation zone, note the authors.
They add that central needle biopsy is believed to have higher accuracy.
While commenting that the review used “best standards”, Klubo-Gwiezdzinska noted the caveat that it provides “low to moderate quality evidence as it included case series or retrospective cohort studies, characterized by an inherent bias associated with these study designs.”
And as the authors also acknowledge, possible overlap in the included cohorts “could mean that sample sizes could be smaller than reported,” Klubo-Gwiezdzinska commented.
To better assess the benefits and harms of RFA, the authors suggest that “future studies could focus on improving rates of complete tumor volume clearance, possibly with more advanced or longer RFA procedures.”
RFA an option for some patients
Meanwhile, lead author Tessa M. van Ginhoven, MD, PhD, from the Department of Surgical Oncology and Gastrointestinal Surgery, Erasmus MC Cancer Institute, University Medical Center Rotterdam, suggests that in addition to cases of tumor growth Locally, possible uses of RFA for micro-PTC could include situations of patient anxiety due to active monitoring.
“If active surveillance is appropriate for your population, but the patient is anxious and prefers lobectomy, RFA might be considered as a possible adjunct to active surveillance,” she said. Medscape Medical News.
The authors and Klubo-Gwiezdzinska did not report any relevant financial relationships.
JAMA Otolaryngol Head Neck Surg. Published February 10, 2022. Abstract