Groundbreaking Study Finds Radioiodine Unnecessary for Low-Risk Thyroid Cancer Patients
Patients with low-risk differentiated thyroid cancer show similar outcomes after five years, regardless of whether they receive radioactive iodine following total thyroidectomy, according to a landmark randomized trial. This finding suggests that many patients can safely avoid the additional treatment, with exceptions for high-risk cases.
“This is the first randomized, prospective trial showing that radioiodine is useless in low-risk thyroid cancer,” said lead author Sophie Leboulleux, MD, PhD, of the Department of Endocrinology and Diabetology at Geneva University Hospitals in Switzerland.
Radioiodine has long been a cornerstone of thyroid cancer treatment.However, recent consensus has shifted toward avoiding the therapy in patients with low-risk follicular cell–derived thyroid cancer, notably those with stage I disease involving unifocal microcarcinomas measuring 10 mm or smaller. For other low-risk thyroid cancers, the evidence has been inconclusive, with some studies showing inconsistent benefits and others none at all.
To address this uncertainty, Leboulleux and her team conducted the multicenter, phase 3 ESTIMABLE2 trial, involving 776 patients in France who underwent total thyroidectomy between May 2013 and March 2017. All participants had a low risk of recurrence, with no suspicious findings on postoperative neck ultrasounds.
Patients were randomized to receive either no radioiodine or radioiodine (1.1 GBq [30 mCi] of iodine-131 after recombinant human thyrotropin–stimulating hormone) following surgery. At three years, the study found that outcomes without radioiodine were not inferior to those with it. The proportion of patients without events was slightly lower in the no-radioiodine group (95.6%) compared to the radioiodine group (95.9%).
Non-inferiority was defined as a less than 5% difference between the groups in the proportion of patients experiencing events, wich included abnormal radioiodine uptake, abnormal neck ultrasounds, elevated thyroglobulin levels, or the appearance of thyroglobulin antibodies.
At five years, the results remained consistent. Among 698 evaluable patients, 93.2% of those who did not receive radioiodine were event-free, compared to 94.8% of those who did, a difference of just −1.6%.
Key factors linked to the advancement of an event included postoperative serum thyroglobulin levels > 1 ng/mL, age between 55 and 60, follicular histology, and larger tumor size. Among 19 patients with elevated thyroglobulin levels, 10 received subsequent treatment, while 6 of the untreated patients (67%) experienced spontaneous normalization of their levels.
“This emphasizes the fact that when thyroglobulin levels are slightly elevated, there is no emergency to administer empiric activities of radioiodine,” the authors noted.
They also highlighted that using postoperative thyroglobulin levels as a parameter for radioiodine governance could drastically reduce the number of patients requiring treatment. While a thyroglobulin level > 1 ng/mL was a prognostic factor for events, the study used a threshold of 2 ng/mL to define events in patients without radioiodine.
“A cutoff of 2 ng/mL could be used as a threshold to give radioiodine to these patients,” the authors suggested. however, they concluded that “proof that the outcome of these patients will be improved by radioiodine is still needed with prospective studies.”
| Key Findings from the ESTIMABLE2 Trial |
|——————————————–|
| No Radioiodine Group | Radioiodine group |
| 93.2% event-free at 5 years | 94.8% event-free at 5 years |
| Difference: −1.6% | Non-inferiority threshold: <5% |
| Key prognostic factors: Thyroglobulin >1 ng/mL, age 55–60, follicular histology, larger tumor size |
This study marks a important step forward in refining treatment protocols for low-risk thyroid cancer, potentially sparing many patients from unnecessary radioiodine therapy. For more insights into thyroid cancer treatment, explore the latest research on radioiodine remnant ablation and its evolving role in patient care.
Headline:
Revolutionizing Thyroid Cancer Treatment: A Conversation with Dr. Patricia 등이关于无需放置低危甲状腺癌患者的放射性碘
Introduction:
In a groundbreaking turn, a recent study led by Dr. Sophie Leboulleux challenges the conventional wisdom regarding radioactive iodine (RAI) treatment for low-risk differentiated thyroid cancer patients. Join us as Senior Editor,Emily Harper,sits down with Dr. Patricia Lee, a renowned thyroid cancer specialist, to discuss the implications of the ESTIMABLE2 trial and its potential to reshape thyroid cancer treatment protocols.
The ESTIMABLE2 Trial: A Game Changer
Emily Harper (EH): Dr. Lee, the ESTIMABLE2 trial has made headlines with its findings that RAI might be unnecessary for low-risk thyroid cancer patients. Can you share your thoughts on this meaningful study?
Dr. Patricia Lee (PL): Absolutely, Emily. The ESTIMABLE2 trial is indeed a game changer. Led by Dr. Sophie Leboulleux, the study randomly assigned 776 low-risk thyroid cancer patients to receive either no RAI or RAI treatment after total thyroidectomy. After five years, the outcomes were remarkably similar, with event-free rates of 93.2% and 94.8% for no-RAI and RAI groups, respectively. This suggests that many low-risk patients can safely forgo RAI treatment, which has long been a standard post-surgery approach.
Refining Treatment Protocols
EH: So, does this mean we should abandon RAI for low-risk thyroid cancer patients altogether?
PL: Not quite, Emily. While the study shows that many low-risk patients could avoid RAI, it doesn’t mean all of them. Certain factors, such as postoperative serum thyroglobulin levels >1 ng/mL, age between 55 and 60, follicular histology, and larger tumor size, were linked to an increased risk of recurrence. Therefore, patient-specific assessments should still be made to determine the need for RAI on a case-by-case basis.
The Role of Thyroglobulin Levels
EH: The study also emphasized the importance of thyroglobulin levels. Could you elaborate on that?
PL: Of course. Thyroglobulin is a protein produced by normal thyroid cells and is often used to monitor thyroid cancer patients’ progress. In the ESTIMABLE2 trial, a postoperative thyroglobulin level >1 ng/mL was a prognostic factor for events. However,a threshold of 2 ng/mL was used to define events in patients without RAI. The authors suggested that a cutoff of 2 ng/mL could be used to decide who might benefit from RAI, but they noted that prospective studies are still needed to confirm this.
Looking Ahead
EH: Dr. Lee, what are the next steps in light of these findings?
PL: The ESTIMABLE2 trial marks an important step forward in refining thyroid cancer treatment protocols. Though, more research is needed to confirm these findings and determine the optimal management for low- to intermediate-risk patients. In the meantime, healthcare providers should consider these results when making treatment decisions, with a focus on personalized approaches to each patient’s needs.
EH: Dr. Lee, thank you for shedding light on this groundbreaking study and its implications for thyroid cancer treatment.
PL: my pleasure, Emily.It’s an exciting time in thyroid cancer research, and studies like ESTIMABLE2 are helping to reshape our understanding and approach to this disease.
