Recurrence due to dissemination of tumor cells after transoral endoscopic thyroidectomy vestibular approach

INTRODUCTION

Cases of thyroid cancer and thyroid nodules have increased significantly in the last decade. Roughly 5% of the female population has a thyroid nodule.^1,2 As a result, surgical procedures have witnessed notable progress, including the advancement of endoscopic surgery techniques.^3,4 One such technique, transoral endoscopic thyroidectomy vestibular approach (TOETVA), allows access to the thyroid gland without leaving visible scars as it is performed through natural openings.^5,6 It is worth nothing that TOETVA is only indicated for certain cancer patients. Initially, questions regarding the potential for postoperative recurrence, including the scarring from trocar insertion, remained unclear.

There are currently no long-term oncological follow-up reports on large group of patients and tumors of larger size.⁷ The present report aims to document a case of recurrence attributed to residual tumor in a patient with papillary thyroid cancer who underwent TOETVA.

CASE REPORT

For nearly a decade, TOETVA has proven to be a viable option for minimally invasive management of thyroid cancer. It is indicated for both benign and malignant tumors, although most case series involve benign tumors.⁶ This is due to safety considerations as residual tumors may be left behind during resection in two ways. Firstly, given the size of the tumor, the thyroid gland may need to be fragmented within the neck cavity, leading to the inadvertent shedding of tumor fragments.⁷ Secondly, a capsular rupture may occur during specimen extraction.

Ultrasound is highly useful in detecting nodal recurrence, while fine-needle aspiration biopsy is deemed an essential resource. Nodal recurrence in patients staged as N0 poses a challenge, as addressing it would require conventional open surgery at the site of recurrence, thus negating the aesthetic benefit provided by TOETVA.

Although TOETVA was introduced ten years ago and has been widely adopted,⁴ there have been no reports of recurrence in the neck, let alone in the surgical area of the thyroidectomy. Nodal recurrence may be underreported, particularly in patients who did not undergo I-131 ablation therapy. This therapy can target microscopic disease, potentially preventing it from manifesting over time.

We have previously reported a series of TOETVA cases specifically involving cancer patients,⁷ as our institute focuses solely on cancer. According to the 2015 American Thyroid Association guidelines, follow-up and surveillance depend on whether patients underwent total thyroidectomy via TOETVA and the initial risk stratification.¹ An ultrasound should be performed 6-12 months after surgery, followed by an assessment of the administration of radioactive iodine based on each patient's status. For low-risk patients who underwent TOETVA, maintaining their TSH levels within the range of 0.5 to 2 mU/l is advisable.² TSH suppression is unnecessary in patients who can maintain their target TSH level. Routine ablation therapy is not recommended in low-risk patients.

Currently, TOETVA is performed in differentiated thyroid cancers with tumors smaller than 2 cm.³ It is advised for lesions requiring ipsilateral lobectomy and isthmectomy to mitigate postoperative complications.⁵ However, total thyroidectomy has not yet become a standard but could be tailored to suit each patient’s needs.⁸

In contrast to the previously mentioned, we do not recommend TOETVA for performing lobectomies or isthmectomies. This is because if a patient later requires an additional total thyroidectomy based on definitive histology, a reoperation would compromise the benefit of achieving a scar-free surgery. Another concern is the possibility of recurrence, as illustrated in this case where thyroglobulin monitoring facilitated the detection of such recurrence. Managing recurrence in partial thyroidectomies would be challenging due to the absence of postoperative thyroglobulin markers. Over time, we anticipate encountering similar reports, like the one presented here, detailing cases of recurrence due to residual tumors or recurrent nodal disease. At present, this seems to be the first reported case.

CONCLUSION

TOETVA remains a safe procedure for cancer cases. However, its oncological outcomes have not yet been fully demonstrated, particularly regarding the impact of possible recurrences stemming from residual tumor fragments or cells during the procedure.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

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