Prospective randomized open phase III non-inferiority trial in cT1bN0N1aM0 isthmus tumors of the thyroid comparing: extended Isthmusectomy (Isthmusectomy + Central Neck Dissection)(experimental group) versus total thyroidectomy + Central Neck Dissection (reference group).
The thyroid isthmus is a narrow structure connecting the two lobes of the thyroid. Papillary carcinoma arising from this site accounts for only 1-9% of all thyroid cancers. However, due to its unique anatomical location, it is more prone to extranodal extension and bilateral lymph node metastasis, exhibiting more aggressive biological behavior. The optimal extent of surgery remains controversial: total thyroidectomy facilitates postoperative radioactive iodine therapy and monitoring but results in permanent dependence on thyroid hormone replacement and increases the risk of complications such as hypocalcemia, adversely affecting patients' quality of life. In contrast, conservative approaches like extended isthmusectomy can preserve partial thyroid function, reduce complications, and maintain a better quality of life, making them particularly suitable for low-risk patients with small tumors and no metastasis. Existing retrospective studies indicate no significant difference in recurrence rates between the two surgical approaches, though the evidence remains limited. Therefore, this study aims to conduct a prospective, multicenter, open-label, parallel-controlled, randomized trial to directly compare total thyroidectomy and extended isthmusectomy in terms of postoperative recurrence rates, quality of life, and complications, thereby providing high-quality evidence for surgical decision-making.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
520
Total Thyroidectomy with bilateral central compartment (level VI) neck dissection - surgical removal of entire thyroid gland and perform bilateral Level VI neck dissection. This is the standard treatment recommended by the Chinese Guidelines for the Diagnosis and Management of Thyroid Nodules and Differentiated Thyroid Cancer (2nd Edition). The participating surgeons all routinely perform complete central neck dissections. They were selected for this study due to their standardized technique, which ensures a consistent surgical approach.
Extended isthmusectomy with bilateral central compartment (level VI) neck dissection : Completely resect the isthmus and portions of the bilateral thyroid gland adjacent to the isthmus, ensuring an R0 resection margin for the tumor, while preserving at least more than half of the bilateral thyroid lobes.
2nd Affiliated Hospital, School of Medicine, Zhejiang University, China
Hangzhou, Zhejiang, China
Rate of 3-year recurrence
defined as thyroid cancer recurrence, metastatic disease from thyroid cancer (whichever occurs first)
Time frame: maximum of 3 years after the surgery
Anatomical location of tumor recurrence
Time frame: maximum of 3 years after the surgery
Risk of surgical site recurrence
recurrence occured in the thyroid bed
Time frame: maximum of 3 years after the surgery
Health Related Quality of Life
Measured using FoP-Q-SF: Scales range from 12-60 with higher scores indicating greater fear of disease progression Measured using THYCA-Qol questionnaires: including 7 symptom dimensions and 6 single items. All items are rated on a 4-point scale (none, a little, quite a bit, very much), scored from 1 to 4. Higher scores on individual items indicate lower quality of life.
Time frame: Baseline (post-randomisation/pre-surgery), 4 weeks and 3, 6,12 months after the surgery
Number of participants with Hormone Replacement Therapy
patients who require thyroxin intake
Time frame: 2-4 weeks and 3, 6, 12, 24, 36 months after the surgery
Rate of surgical complications
including transient/permanent hypoparathyroidism, transient/permanent recurrent laryngeal nerve injury, postoperative infection, and postoperative lymphatic fistula.
Time frame: perioperatively, 2-4 weeks, 6 months after the surgery
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